History of Psychiatry

History of Psychiatry. Introduction

Psychiatry is a branch of medicine that deals with the diagnosis, and treatment, of mental health illnesses. Psychiatry is an extraordinarily diverse, scientifically interesting, and therapeutically successful field ranking among the medical specialties with the greatest advancements in recent decades.

The history of psychiatry deals with the historical development of scientific, social, and medical approaches to mental illnesses.

The understanding of mental illnesses has changed over time. It shifted from religious explanations (demonic possession, karma) to humoral pathology (imbalance of bodily fluids), as described in the Corpus Hippocraticum and expanded by Galen. A notable fact is the striking similarity in fundamental psychiatric questions across ancient, mediaeval, and modern medicine, such as the relationship between mental disorders, the culture, and the affected person. Other recurring themes include the significance of somatic (brain) dysfunctions in the development of mental illnesses.

Psychiatric knowledge and practice have the most complex connections to intellectual and social history within medicine. Thus, any brief overview of psychiatric history risks oversimplification. The following summary can only serve as a basic introduction and cannot replace in-depth literature study.

The structure of this article follows the chronology of key psychiatric concepts from antiquity to the present.

Mental illness in Prehistoric Times

Our understanding of prehistoric times, before the discovery of writing, remains incomplete. Nevertheless, it is plausible to assume that in those times humans perceived a world teeming with spirits. They explained the phenomena of nature and the unknown through the lens of magic.

Living in a world inhabited by imagined entities, these spiritual forces served as a balm for the human anxieties. The humans projected into them their inner turmoil and confusion.

In the early civilisations, people developed mythologies populated with gods and good-like creatures serving them to understand the phenomena of nature.

The sacred approach in the ancient times can be categorized into three phases: “animistic,” “mythological,” and “demonological.” Despite their differences, they all shared the belief that abormal human behaviour recognized today as psychiatric ilnessess stemmed from transcendent magical actions influenced by external forces.

The Animistic Phase

The primitive humans believed that unexplained behavior was influenced by animistic spirits. This model relied on pre-logical and emotional reasoning, attributing events to mysterious, forces within the natural world such as wether, animals or plants. In this view, animated entities acted upon human minds and souls. Magic and supernatural concepts provided explanations for the unfathomable and unpredictable.

The Mythological Phase

transformed these vague forces into concrete myths. Every aspect of life was linked to specific entities, and disorders were believed to be caused by deities who could cure them if properly implored.

The Demonological Phase

incorporated transcendent mythological deities into formal theological systems, such as Judeo-Christian beliefs. Here, two opposing forces vied for dominance: one positive, represented by a benevolent God, and the other negative, manifested as destructive demonic forces of evil.

These spirits, both good and evil, were thought to inhabit individuals with mental disorders, creating fear of demonic possession as punishment for defying gods. Primitive “therapies” like shock, starvation, and surgery, were rooted in this naively simplistic demonological belief system.

Prists and Magicians

In this worldview, priests and magicians exerted significant influence in societies. They exploited people’s fears, claiming the ability to “cure” physical ailments, and “cleanse” mental disturbances. They provided solace in the face of life’s ever-present fears. The prists and magicians were organized in hierarchical system, where healing was monopolized by a select few, continues to persist in certain cultures until today.

Babylonia, India, China

The early contributions of India, Babylonia, and China offer insights into ancient perspectives on mental health.

Babylonia

In Babylonia, a vast civilization in the Middle East, philosophical ideas influenced the Mediterranean region. Many Greek and Roman traditions can be traced back to Babylonian concepts. Babylonians were fascinated by astronomical events, attributing divine significance to stars and celestial bodies. They believed in conflicts among gods and sought help through magical rites, prayers, and the powers of physicians or priests. The Babylonians assigned a demon to each disease, linking supernatural forces to illness. For instance, insanity was attributed to the demon Idta.

Ancient China

China’s earliest medical text, Neijing, from 300 B.C. to 100 B.C., described ilnessess such as epilepsy and delirium. Psychiatric illnesses were attributed to factors like bad air, weather, and emotional stress. Chinese medicine relied on philosophical concepts, including yin and yang. It linked personality types to the five elements: gold, wood, water, fire, and earth.

Chinese medicine later focused on organ functions, attributing the heart to the mind, liver to the spiritual soul, lung to the animal soul, spleen to ideas and intelligence, and kidneys to vitality and will, overlooking the brain. In China, acupuncture, traditional medicine, folk herbs, and “talk therapy” were common treatment approaches.

Psychiatric and physical symptoms intertwined. The mind-body connection wasn’t emphasized. Mood disturbances and psychiatric symptoms were linked to menstrual irregularities, often expressed somatically. For example, the Chinese word for “depression” meant “stagnation,” symbolizing blocked vital air circulation. Chin-Yue’s Medical Book presented cases of “deceiving sickness” (hysterical neurosis) in challenging situations. Sexual impotence was attributed to excessive worry. China’s psychiatric concepts followed a sequence similar to the West: supernatural, natural, somatic, and psychological stages. However, Chinese medicine was less influenced by religion compared to early European medicine.

Ancient India

Indian cultures have a longstanding interest in understanding and addressing mental disorders. In India, Susruta, predating Hippocrates, acknowledged the link between strong emotions and mental disorders. Hindu medicine recognized three innate inclinations: enlightened goodness in the brain, impetuous passions in the chest, and animalistic instincts in the abdomen. Caraka Samhita, a prominent text, defined life as a combination of body, psyche, and soul, emphasizing the role of the mind in cognition and self-control.

Ayurveda, the first formal Indian medical system, integrated physical and mental health, emphasizing the importance of equilibrium between the self and the mind. The Hindu system incorporated the concept of doshas, similar to humors in Greek medicine. Food types were believed to influence personality and mental health.

Different personality types were associated with mental illness, attributed to factors like diet, temperament, and heredity.

Ancient Egypt

In ancient Egypt, the heart was considered the center of mental activity. Supernatural beliefs intertwined with observable phenomena; primarily astronomical events worshipped as gods’ mystical powers. Over time, Egyptian scholars studied the brain, recognizing it as the source of mental activity. Emotional disorders, akin to Greek ideas, were explained as “hysteria” caused by a wandering uterus, treated by repositioning it.

Ancient Greece

In early Greek civilization, insanity was viewed as divine punishment for transgressions. Therapy involved expiatory rituals to cleanse impurities causing psychic disorders. Priests mediated prayers for divine intervention.

In the later ages Greeks realized their irrational approach to mental pathology needed change. They transitioned from supernatural explanations to a more concrete, natural perspective. This transformation was driven by imaginative thinkers in the 5th and 6th centuries B.C. Greek philosophers such as Thales and Pythagoras sought to simplify the universe by identifying its fundamental element, whether water, air, or fire.

Pythagoras

Pythagoras emphasized the importance of identifying scientific principles to explain all forms of behaviour. Pythagoras claimed that the brain was the seat of human intellect and the source of mental disturbances, a groundbreaking assertion in his time. He introduced concepts such as biological humours and emotional temperament to decode the origins of abnormal passions and behaviour. He believed that these principles could be applied not only to mental ilnessess but also to human character, ethics, and religion. He saw mental life as a reflection of harmony between antithetical forces, such as good versus bad and love versus hate. He believed that life itself was regulated by opposing rhythmic movements, such as sleep and wakefulness or inspiration and expiration.

Mental disorders, in Pythagoras’ view, arose from a disequilibrium of these fundamental harmonies, leading to symptoms of psychic impairment. To him, the soul had the capacity to rise or descend from and to the body, with a healthy and balanced soul resembling solar energy.

Pythagoras divided the soul into three parts: reason, which represented truth; intelligence, responsible for synthesizing sensory perceptions; and impulse, deriving from bodily energies. The rational aspect of the soul resided in the brain, while the irrational aspect resided in the heart.

Plato

Plato, one of the most influential philosophers of ancient Greece, made significant contributions to understanding the mind and its complexities. He identified several key themes relevant to mental processes and disorders. Firstly, he posited that powerful emotional forces could disrupt an individual’s typical behaviour. These forces could bring intense emotions to the forefront, overwhelming rational thought and daily actions. Secondly, Plato highlighted the potential for conflicts within the psyche. He described the tension between rational desires and emotional impulses, noting that this internal discord could impact personal behaviour and mental health.

Additionally, Plato argued that mental disorders stemmed not from ignorance but from irrational superstitions and erroneous beliefs. He believed that all humans had an animal-like nature, leading to occasional irrational behaviour. This idea was supported by his observations of dreams, where bizarre events and unnatural connections among thoughts and images frequently occurred.

Plato contended that therapeutic efforts could address and modify all forms of mental illness. He advocated the dialectical model, which involved rational discussions to change patient’s belief systems, laying the groundwork for contemporary cognitive therapies.

Aristotle

Plato’s most distinguished student, Aristotle, diverged from his teacher’s abstract and idealistic approach, favouring more realistic and tangible matters. Aristotle, a philosopher and scientist, provided history’s first integrated and systematic accounts of psychology, astronomy, physics, zoology, and politics. Unlike Plato, Aristotle emphasized the need for experimental verification and the use of sensory-based observable data. He was the first major philosopher to adopt an inductive and empirical approach, focusing on concrete experiences registered through the senses.

Although Aristotle admired Plato’s abstract rationalism, he preferred dealing with the tangible world over high-order abstractions or broad principles. He believed that data should be grounded in empirical observables to minimize subjective misinterpretations. Despite his empirical approach, Aristotle recognized that thought transcended the sensory realm. He posited that imagination could generate higher-order abstract thoughts beyond mere sensory experiences.

However, not all of Aristotle’s theories were accurate. Despite evidence that the brain was the center of thought and emotion, he erroneously believed that the heart was the seat of these psychological experiences. Nonetheless, Aristotle made significant contributions to understanding cognitive processes, dreams, and emotional catharses. He observed that events, objects, and people were linked by their relative similarity or difference, a concept that anticipated the associationist school of the 18th and 19th centuries. Aristotle viewed dreams as afterimages of the preceding day’s activities, recognizing their potential biological function and using their content to gauge potential pathology.

Aristotle’s broad and inventive scope extended to the intellectual and motivational features of the mind from a natural scientist’s perspective. He proposed a psychobiological theory outlining the basics of human perception and rational thought, emphasizing the importance of sense impressions for objective experimental study. Aristotle also articulated a model of learning based on the principles of association, reinforced by what is now termed the “pleasure principle.” He emphasized the importance of early experience and education in skill acquisition and the role of habit and practice in forming psychological attitudes.

Theophrastus

Theophrastus (371-286 B.C.), a decade younger than Aristotle, had travelled to Athens to study with Plato. He and Aristotle were friends who travelled together and studied nature. Theophrastus’ focus on botany made him the actual inventor of the subject, similar to how Aristotle developed zoology.

Theophrastus, a prolific and intelligent thinker, published 220 treatises on various topics. While he produced a wide range of work, he was most well-known for his “characters,” or personality sketches. Each portrayal emphasised a psychological trait, presenting a “vignette” of different personality “types” (e.g., flatterers, garrulous, penurious, tactless, boorish, surly, etc.).
Theophrastus and succeeding novelists were allowed to write about their subjects without psychological or scientific restraints not matching todays scientific criteria.

Alcmaeon

Alcmaeon was a philosopher-physiologist from the 5th century B.C. who laid the foundation for a scientific approach to mental health. He was possibly a son or favored student of Pythagoras.

One of Alcmaeon’s most important contributions was his meticulous exploration of the brain and nerves through anatomical studies. His most revolutionary idea was the proposition that the brain, was the organ responsible for thought challenging the prevailing idea that the heart was the seat of thought and consciousness.

Alcmaeon’s ideas also resonated with the works of figures like Aesculapius, Empedocles, and Hippocrates. He shared their belief in the importance of balance among the essential bodily fluids. The balance between cool versus warmth, wet versus dry achieving equilibrium was seen as crucial for both physical and mental health.

Alcmaeon’s “biological model,” which he termed “isonomy,” replaced the earlier mythological theology prevalent in ancient Greece. This transition reflected the growing secular and democratic spirit of Greek culture in the 6th century B.C.

Empdocles

Empedocles was another influential philosopher of the time. He adopted and expanded upon the homeostatic model that emerged from the works of Pythagoras, Aesculapius, and Alcmaeon. His contributions added depth to the understanding of the four basic elements of life: fire, earth, air, and water. He believed that achieving balance among the four elements was crucial for physical and mental health. However, he also pondered the consequences of different combinations of these elements. Empedocles introduced additional concepts of “love” versus “strife” as principles influencing these elements. He concluded that “love” would bring forth a harmonious unity, while “strife” would lead to personal breakdown or social disintegration. His insights extended the understanding of the human psyche and its connection to the natural world.

Hipocrates

Hippocrates  (460 – 370 BC), was a Greek physician and philosopher of the classical period. Born on the island of Cos, the son of an Aesculapian priest, imbibed his father’s medical knowledge and integrated it with the teachings of Pythagoras and Empedocles. He embarked on a journey that would transform the landscape of medicine. He is considered one of the most important figures in the history of medicine and traditionally seen as the “Father of Medicine.” His lasting contribution was the introduction of empirical observation and systematic categorization of diseases. He also proposed and formulated the humoral theory. The Hippocratic school of thought revolutionized ancient Greek medicine, establishing it as a profession.

Hippocrates transitioned mental health from the era of magic and superstition to one of careful clinical observation and inductive theorizing. Rejecting the idea that mental disorders were caused by supernatural forces, he emphasized that all disorders, whether mental or physical, had natural causes.

For Hippocrates, the brain was the epicenter of thought, intelligence, and emotions. He recognized that the brain was responsible for both joy and sorrow, laughter and tears, and even madness. This emphasis on the brain as the seat of mental activity laid the foundation for later neuroscience.

Hippocrates’s approach was deeply empirical. Unlike philosophers who relied on abstract hypotheses, he focused on observable symptoms, treatments, and outcomes. In his pursuit of understanding mental disorders, Hippocrates introduced the practice of carefully recording personal case histories, offering insights into various psychological conditions.providing early descriptions of disorders such as depression, phobias, convulsions, and migraines. His attention to temperament, associated with the four-humors model, laid the groundwork for characterizing individuals based on their predominant bodily elements. He providedearly descriptions of disorders such as depression, phobias, convulsions, and migraines. His attention to temperament, associated with the four-humors model, laid the groundwork for characterizing individuals based on their predominant bodily elements. Such approch was the first trial to establish human typology.

Dreams were another area of interest for Hippocrates. He believed that dreams could serve as indicators of a person’s health or illness. Disparities between dream content and reality, in his view, could be a sign of mental pathology. This perspective foreshadowed later theories about the role of the unconscious and the dream symbolism.

Aretaeus

Ancient Rome

The Roman period, spanning from the 7th century B.C. to the 5th century A.D., was marked by significant advancements in understanding mental health. During this era, the Roman Republic (5th century B.C. to the 3rd century A.D.) made considerable efforts to eliminate magic and superstition from considerations of mental processes. Instead, a mechanistic and materialistic conception of mental disorders emerged, rejecting transcendental mythologies as products of fear and ignorance. The Romans believed that mental disorders were not caused by mysterious forces or biohumoral imbalances but by the periodic enlargement or excessive tightening of the brain’s pores. This corpuscular hypothesis, derived from Democritus’s atomistic notions, posited that mental health could be maintained by normalizing the diameter of these pores.

In this context, individuals with mental illnesses were categorized based on their symptoms. Those who were apathetic, fearful, and depressed were considered to be in a laxum state, while those who were excited, delirious, and aggressive were in a strictum state. A mixtum state was identified when both sets of symptoms co-occurred. This early classification system highlighted the Romans’ attempt to systematically understand and address mental health issues.

Aretaeus

Aretaeus (30–90 A.D.) is one of the most renown ancient Greek physicians probably born in Cappadocia, a Roman province in Asia Minor. He connects the Greek and Roman schools of philosophy contributing significantly to the humanistic school of thought in early Rome.

Aretaeus adopted the concept of pneuma, the natural or animal spirit, as the physical embodiment of the soul. According to Aretaeus, the interconnections among solid organs, humors, and pneuma generated all forms of mental aberration. For instance, anger and rage stirred yellow bile, increasing brain temperature and leading to irritability, while fear and oppression stirred black bile, resulting in melancholy.

Recognition of clinical observation

Aretaeus introduced long-term follow-up studies of patients. He tracked their lifetime course, disease manifestations, and return to normal health. This approach anticipated Emil Kraepelin’s later recognition of the course of an illness as a key factor in distinguishing specific disorders.

Aretaeus’s perceptive observations strengthened the notion that mental disorders were exaggerated normal processes. He identified patients’ premorbid states as indicators of vulnerability to clinical syndromes. According to Aretaeus, individuals with mania exhibit traits such as irritability, violence, joy, and a preference for childlike activities. Individuals with depression and melancholia were characterized as “gloomy and sad, often realistic but prone to unhappiness.” His differentiation of disorders according to symptom constellations, was a remarkable achievement for his time.

Description of mental illnesses

Aretaeus, unlike other physicians of his time, not only described psychological conditions with sensitivity and humanity but also sought to compare and differentiate clinical syndromes in a manner similar to modern scientific research.

Aretaeus’s descriptions of epilepsy were particularly impressive, detailing premonitory symptoms such as vertigo, nausea, and the perception of sparks, colors, harsh noises, or nauseating smells. He also explored the origins and characteristics of fanaticism and formulated a primitive psychosomatic hypothesis, suggesting that emotions could affect humoral metabolism. He described cyclothymia, noting the alternation of depression with phases of mania, and identified various types of mania, including those characterized by superficiality, childishness, and grandiosity.

Hippocrates may have been the first to describe depression medically, but it was Aretaeus who provided a complete and modern portrayal of the disorder. He proposed that melancholia had psychological causes, unrelated to bile or other bodily humours. Aretaeus also recognized the covariation between manic behaviours and depressive moods, describing for the first time a condition Kraepelin called manic-depressive ilness.

Aretaeus’s legacy lies in his detailed descriptions of psychological conditions, his humane understanding of patients, and his efforts to compare clinical syndromes. His work laid the groundwork for modern psychiatric diagnosis and treatment, highlighting the importance of empirical observation and long-term patient care. His contributions underscore the progress made in understanding mental health during the Roman period, bridging ancient and contemporary schools of thought.

Claudius Galenus (131 to 201 A.D.)

commonly known as Galen, was a pivotal figure in Roman medicine, living from 131 to 201 A.D. A Greek subject of the Roman Empire, he was born in Asia Minor and witnessed significant political and cultural changes in Rome during his lifetime. Galen played a crucial role in preserving earlier medical knowledge while also introducing his own significant contributions. Living over 600 years after Hippocrates, Galen followed the Hippocratic emphasis on observation and systematic evaluation in medical practice. He argued against untested primitive and philosophical hypotheses, advocating instead for those based on empirical evidence.

Galen’s Spiritus Anima

Galen, influenced by both Aristotle and Hippocrates, prioritized experiential data over logical hypotheses lacking factual support. Despite this empirical approach, he doubted that environmental and psychological factors could influence the course of human disease. He avoided philosophical discussions about illness but introduced the concept of “spiritus anima,” suggesting that humans possessed an extraphysical life-giving force, distinguishing organic from inorganic matter.

Galen divided these animalistic spirits into two groups: those responsible for sensory perceptions and motility, whose impairment would cause neurological symptoms, and those with directive functions, such as coordinating imagination, reason, and memory. He attributed most psychiatric symptoms to alterations in the second group of functions. In his description of catatonic psychosis, Galen suggested that a paralysis of the animal spirits led to a blockage or incompletion of the imaginative faculty. He disagreed with Hippocrates’s view of hysteria, which attributed the condition to a wandering uterus. Instead, Galen proposed that hysterical symptoms were caused by toxic vapors formed in the normal uterus and vagina due to a lack of sufficient sexual intercourse, indicating a deficiency in sexual hygiene.

Galen’s Humoral Theory

Galen’s understanding of psychic pathology centered on the physiology of the central nervous system. He viewed clinical symptoms as signs of dysfunctional neurological structures and described mental diseases as a collection of symptoms, among which a specific pathognomonic symptom could be identified. According to his organic functional approach, mental symptoms arose from the pathogenic action of various factors—such as toxins, humours, vapours, fever, or emotions—that physically affected the brain and altered its psychic functions.

Between Ancient Thoughts and Medieval Superstitions

Galen’s work represents a bridge between the empirical approaches of ancient Greece and the superstitious beliefs that dominated later Roman and medieval thought. On the one side he emphasised on observation and empirical evidence, on the other side he believed that the mind’s activities were driven by animal spirits (pneuma). His understanding of mental health conditions set the stage for future medical advancements, even as his ideas were overshadowed by the influence of supernatural forces contributing to mental illness.

Galen’s influence grew over the next millennium, with his views becoming almost sacrosanct. Many lesser physicians summarized and commented on his writings, although some misrepresented his work to promote their ideas. Despite the dilution and refutation of some of his notions over time, Galen’s contributions were significant, with no other figure in history exerting such an extended influence on medicine.

Early Christianity

As Roman history progressed, an organized theology known as Christianity emerged, incorporating faith healing, magic, and superstition. The early Christian church’s doctrine dominated Western thought, medicine, and mental healing until the 17th century. During this period, most of the populace remained illiterate, and education was largely religious and of questionable value. The scientific basis for understanding mental disorders barely appeared, with faith being the predominant guide.

In the first two to three centuries A.D., a distinction was made between psychologically normal individuals who doubted the church’s dogma and those whose peculiar beliefs were attributed to mental affliction. Both groups were considered heretical and faced punishment. Conversely, implausible or nonsensical behaviour demonstrating fervent adherence to church authorities was venerated. This led to the condemnation of works by Aristotle and other Greek philosophers.

By the 3rd century, Christianity had led physicians to adopt a moralistic and judgmental approach to psychic pathology. They proposed that mental disorders were products of mystical events beyond natural understanding. Physicians believed demons often appeared as confused humans and saw it as their duty to identify and eliminate these demons. This laid the groundwork for a return to supernaturalism and superstitions, an approach that persisted until the close of the 17th century.

St. Augustine (354–430)

Aurelius Augustine, known as St. Augustine of Hippo, was crucial in transitioning from early Roman thought to the Middle Ages. His writings aimed to synthesize Greek and Christian perspectives on mental maladies. As a leading philosopher, Augustine shaped Christian intellectual life for centuries. He believed that all knowledge stemmed from God, who alone could provide ultimate truth. Knowing God was the ultimate goal, and deviating from this belief led to error and corruption. Augustine emphasized that individuals, as children of God, could understand life’s nature through faith, thereby leading lives of grace and honor.

Medicine and Psychology in Early Islam

The early Muslim world saw significant contributions to medical and psychological thought from notable figures such as Rhazes, Unhammad, and Avicenna. These individuals introduced innovative ideas regarding mental illness that left a lasting impact on medical history.

Rhazes (860–930)

was a prominent figure during the late 9th and early 10th centuries, known for his extensive writings on medical, psychological, philosophical, and religious subjects. Unlike the predominant religious orientation in Baghdad, Rhazes vehemently opposed the demonological concept of disease and the arbitrary use of authority to define scientific truth. He challenged the superstitious beliefs of his time and advocated for a rational approach to understanding disorders. Although empirically oriented, Rhazes adhered to the theory of the four elements developed by Empedocles and Hippocrates, integrating it into his rational framework.

Unhammad (870–925)

a contemporary of Rhazes, made significant strides in the classification of mental disorders. His detailed observations of patients culminated in a comprehensive nosology, the most complete of its time, describing nine major categories of mental disorders encompassing 30 different diseases. Among his contributions was an excellent description of anxious and ruminative states of doubt, which align with today’s understanding of compulsions and obsessions. Unhammad also identified degenerative mental diseases and those associated with the involutional period of a man’s life. He borrowed the Greek term for mania to describe abnormal excitement and detailed grandiose and paranoid delusions, where the mind magnifies personal significance, often leading to socially outrageous actions.

Avicenna (980–1037)

often referred to as the “Galen of Islam,” was a highly influential philosopher and physician. His encyclopaedic work, the Canon of Medicine, became the medical textbook of choice in European universities from the 10th century onward. While Avicenna was more a systematiser than an original thinker, he synthesized all prior knowledge related to medical events. Like Galen, Avicenna emphasized the connection between intense emotions and various medical and physiological states, though he fully embraced Hippocrates’s humoral theories of temperament and mental disorder. Avicenna’s scholarly contributions included speculations on the brain’s role in intellectual dysfunctions, proposing that deficits in the brain’s middle ventricle could cause such issues and that the frontal areas mediated common sense and reasoning.

These early Muslim scholars significantly advanced the understanding of mental health, moving away from superstitious and demonological explanations towards a more rational and empirical approach. Rhazes championed rationality and empirical methods, Unhammad provided a detailed classification of mental disorders, and Avicenna synthesized previous knowledge while contributing his own insights into the brain’s functions. Their combined efforts laid the groundwork for future developments in medical and psychological science, influencing both the Muslim world and European medical practices for centuries.

The Dark Ages in Europe

The Middle Ages, often referred to as the Dark Ages, was a period marked by significant upheaval, superstition, and a stark departure from the enlightened ideas of ancient scholars like Hippocrates. Following the fall of the Roman Empire, the advanced medical and naturalistic knowledge of the Greco-Roman era was largely forgotten or suppressed. Instead, Europe witnessed a resurgence of demonology, superstition, and exorcism, culminating in the tragic witch hunts and widespread fear of Satanic influences.

The Decline of Hippocratic Thought

The enlightened principles of Hippocrates, which emphasized natural explanations and treatments for illnesses, were almost entirely abandoned after the death of Galen and the collapse of the Roman Empire. For nearly a thousand years, Europe was engulfed in a period where primitive beliefs and practices dominated. During this time, the naturalism of the Greco-Roman period was condemned or twisted into notions of magic and demonology. The Middle East, in contrast, managed to preserve the humane and naturalistic aspects of Hippocratic thought, remaining a beacon of scientific progress amidst Europe’s darkened state.

Superstition and Fear in Medieval Europe

In medieval Europe, signs of demonic possession became increasingly indiscriminate, often linked to widespread famine and pestilence. The destitute and mentally ill were scapegoated, their haggard appearances and confusion used to justify fears of demonic curses. This period was characterized by wild mysticism and mass hysteria, leading to phenomena such as “tarantism” and St. Vitus’s Dance, where entire communities would engage in frenzied dancing and other erratic behaviours, believed to be driven by demonic possession.

The Inquisition

Monasteries initially offered refuge to the mentally ill. They provided cures through prayer, incantations, and mild exorcism. But as natural disasters and societal turmoil increased, views changed. Mental disorders were seen more as evidence of sin and Satanic influence. Theological beliefs evolved, depicting the afflicted as willing followers of Satan. This led to brutal punishments, including flogging, starvation, and burning.

A major driver of these practices was the belief in a Satanic conspiracy. Religious leaders, including Pope Gregory IX, spread this myth. In 1233, the Inquisition was established to root out heretics and witches. These supposed agents of Satan were believed to threaten Christianity and society. Manuals like the Malleus Maleficarum detailed how to identify, interrogate, and punish accused witches. This book, by Heinrich Kramer and Johann Sprenger, fueled the hysteria even more.

The consequences of this fear and superstition were disastrous. Torture was often used to force confessions from accused witches. Many were executed by strangulation, beheading, or burning. This brutal wave of persecution swept across both Protestant and Catholic regions, even reaching American colonies.

Transition to the Modern World

The transition to the modern world began in the 15th century. In this period the focus shifted on humanism and scientific inquiry. Figures like Desiderius Erasmus (called Erasmus of Rotterdam) and Juan Luis Vives emerged. They challenged the dogmatic and superstitious beliefs of their time. Erasmus, a churchman, promoted a new humanistic view on Christ’s teachings. He opposed the rigid rituals and corruption within the Church. Vives, a Spanish Jew, made important contributions to educational reforms. He also showed deep concern for the mentally ill, advocating for humane treatment.

From the 17th Century to the Enlightenment

The guiding thought of the Enlightenment became rationalizm. The word “science” acquired a positive meaning. The convinced rationalists of the 18th century believed there were no fundamentally unsolvable problems, only temporary ones. These authors were firmly convinced that reason, or “ratio,” would eventually penetrate every aspect of human knowledge and action. Rationalism created the intellectual framework that became a science in today’s meaning, explicitly oriented toward mathematics and empirical natural research.

This transformation laid the foundation for a more rational view of mental illness. It moved away from the primitive, demonological interpretations of the Middle Ages. Accepting psychological processes as natural, not metaphysical, marked modern psychiatric thought’s beginning. This shift led to more humane and scientific approaches to mental illnesses.

In this period several important books on psychiatric issues appeared. Among them were Felix Plater‘s Medical Practice (1536–1614) and Robert Burton‘s Anatomy of Melancholy (1621). Although the tendency to label and persecute the mentally ill as possessed gradually declined the new humanitarian ideas were increasingly counteracted by a growing tendency to view the mentally ill as mere outcasts of society, who, should be marginalized.

The major psychiatric hospitals in Paris, such as Bicêtre and Salpêtrière, were initially a mix of poorhouse, prison, homeless shelter, orphanage, and psychiatric clinic. The involvement of doctors was not the norm. This situation occupies a central role in Michel Foucault’s primarily philosophical and social-critical perspective, which is also critical of psychiatry. For him, it serves as a defining identity, but in a negative sense.

New Psychiatric Self-Understanding

The significant interest that the “Enlightened Age” had in the phenomenon of mental illness, especially in psychotic manifestations, or “madness,” is a telling example of the essential link between intellectual history and psychiatry. The central idea of Enlightenment thinking was that humans are rational beings. Psychosis strips a person of this rationality, affecting them at a crucial point, which in turn calls on others to help restore their “rational” state.

Compassion for the mentally ill, rather than their literal demonization, and the diagnosis and treatment of patients, instead of mere exclusion, increasingly became focal points of psychiatric self-understanding. Across Europe, new psychiatric clinics were established. A new attitude took hold in these clinics, leading to the often-cited “liberation of the mentally ill from their chains” at the end of the 18th and the beginning of the 19th century. Examples include Philippe Pinel at Bicêtre in Paris (1793), William Tuke in York (1796), and Johann Gottfried Langermann in Bayreuth (1805).

Two further innovations from the Enlightenment period in psychiatry also deserve mention.

The Birth of Modern Psychiatry

Before the end of the 18th century, there was no psychiatry. Psychiatry in a stricter sense began in the 18th century, influenced by the Enlightenment. The perception of psychiatric patients changed seeing them as individuals without associating them with witchcraft or as a burden for society.

Starting with the first asylums at the end of the 18th century, it evolved and culminated in the quiet practices of private psychiatrists of the late 20th century. First in the late 19th century, psychiatry has developed into an academic science. Recent development of biological psychiatry is another milestone on the “neuroscientific path to success.”

In modern psychiatry, two perspectives dominate. One is the explanation of mental illnesses through brain metabolism disorders. The other is a psychological understanding that sees mental phenomena at an individual level as a result of repressed conflicts or trauma; at a collective level, it is seen as the outcome of a dysfunctional family system or social misery.

The sociohistorical background of modern institutional psychiatry lies in Europe’s population explosion and the resulting social issues. As early as the 17th century, more doctors began to see mental disorders as a medical problem. The Scottish physician George Cheyne (1671–1743) noted that about one-third of his patients suffered from hysterical, neurasthenic, and hypochondriacal syndromes, which he called “The English Malady.” Georg Ernst Stahl (1659–1734) emphasized the role of the soul in somatic illnesses and already distinguished between organic and functional disorders. However, it wasn’t until the end of the century that clinical psychiatry, linked to care in asylums, began to develop.

The modern history of psychiatry usually begins with the “liberation” of the insane in Parisian hospitals Bicêtre and Salpêtrière by the physician Philippe Pinel.

Philippe Pinel and the “French School”

In 1801, the main work of the French physician Philippe Pinel, Traité médico-philosophique sur l’aliénation mentale ou la manie, was published. This marked the breakthrough of a pragmatic, eclectic, and humane approach to psychiatry, which had already been advocated by earlier, mostly French authors. Pinel was skeptical and even openly dismissive of speculative hypotheses regarding the origins and “location” of mental illness. While he adopted many assumptions from earlier authors in his classification of mental disorders into mania, melancholy, dementia, and idiocy—such as linking mania to the abdomen and disrupted functions in the visceral ganglia—he consistently emphasized the need for factual descriptions of clinical phenomena within their individual biographical and social contexts.

For Pinel, unbalanced emotions, improper education, life crises such as puberty or retirement, and purely physical influences could all lead to psychotic illnesses. Like Reil, Pinel had a broad, person-centered, and relatively undogmatic understanding of mental disorders. This approach appeared decades before the rise of natural scientific methods in medicine and psychiatry led to the ongoing polarization between naturalistic and person-centered approaches, a topic that will be revisited.

“Liberation of the Insane from Their Chains”

Pinel consistently rejected mechanical or other coercive measures in treating psychotic patients and criticized the barbaric devices of the time, describing the underlying theories as more misguided than his patients’ delusions. The “liberation of the insane from their chains,” which he carried out in the Parisian clinics he directed—Bicêtre in 1793 and Salpêtrière in 1795—was thoroughly justified and defended against criticism, making his name internationally known. Weiner (1980) wrote about these events and the crucial role of Pinel’s assistant, Pussin. Efforts to eliminate coercive measures in early 19th-century psychiatry occurred in many countries. In the English-speaking world, John Conolly (1794–1866) led this movement, developing and implementing the “no-restraint” concept.

Eclectic Standpoint

In their approach, Pinel and his most influential student, Jean-Etienne Dominique Esquirol (1772–1861), were clinical pragmatists. Grounded in enlightened humanism, they brought significant changes to contemporary psychiatry, took an eclectic standpoint, and were cautious about theoretical approaches, especially those that appeared dogmatic.

Changing Meaning of Psychiatric Terms

Clinical terms, especially the most common ones, are products of complex intellectual history and have often changed, or even swapped, their meanings. The term “neurosis” illustrates this well. For a long time, the most widespread understanding was psychogenetic, primarily psychoanalytic, which viewed neurotic symptoms as indirect expressions of unconscious but persistent psychological processes. Originally, however, at the end of the 18th century, the term “neurosis” was coined by the Scottish clinician Cullen. It was based on Albrecht von Haller’s neurophysiological theory of the sensitivity of neural structures and the irritability of muscle tissue. Thus, it had a purely somatic background, where “neurosis” in its original sense referred to a disturbance in the excitability of the nervous system.

Today, within the framework of operational psychiatric diagnostics, many authors find so little consistency in the term “neurosis” that, similar to the term “endogenous,” it is seen as obstructive and scientifically unnecessary. However, it should not be overlooked that eliminating a term does not remove the issue it addressed, no matter how imprecisely it might have done so. The term “psychiatry” also first appeared during this period, in the works of Johann Christian Reil (1759–1813), who was the city physician of Halle and later a professor of medicine at the newly founded University of Berlin.

Barbaric Treatment Methods

It is particularly noteworthy that Enlightenment-era psychiatry, despite its fundamental focus on reason as a central human trait, developed, promoted, and applied a range of “treatments” that, from today’s perspective, appear extremely irrational and even barbaric. Many of these treatments were based on the idea of shocking or physically straining the mentally ill so severely that the symptoms of psychosis would either recede or, in the best case, disappear entirely. Patients were spun around in a rotating chair, a trapdoor would suddenly open while crossing a bridge, causing them to fall into water, starvation diets were enforced, and even castrations were performed.

Concept of “Moral Insanity”

An important conceptual innovation to note is the creation of the diagnostic category “moral insanity” by the English psychiatrist James Cowles Prichard (1785–1848). This term referred to individuals who disregarded commonly respected social values, pursued their interests in a selfish and ruthless manner, and did not recognize the inappropriateness of such behavior, at least concerning themselves. Clear echoes of this concept are found in later theories of psychopathy. The modern “antisocial personality,” widely discussed in forensic psychiatry and debated as a treatable mental disorder, also shares many similarities with Prichard’s approach.

From the Enlightenment to “Romantic Psychiatry”

Franz Anton Mesmer

Franz Anton Mesmer (1734–1815) occupied a peculiar position between the rationalism of the 18th-century Enlightenment and the subject- and emotion-focused Romanticism, which leaned towards speculative natural philosophy in the early 19th century, particularly in medicine and psychiatry. The core of his theory was the idea that the cosmos consisted of various subtle “streams of fluid,” which he thought of as material. The finest of these streams was indivisible. Mesmer called its special effect in living beings “animal magnetism.” However, he did not envision a rigid, atomistic corpuscular theory but emphasized an unspecified “interaction” between these streams. This conceptual vagueness rightly attracted many critics and contributed to the complex history of Mesmerism’s reception.

Crucially, Mesmer saw himself as an “enlightener,” a discoverer of a universal natural law that extended beyond just medicine. Consistently—and critics would say obsessively or even fanatically—he defended this theory, expanding it to a full theory of society, overshooting the mark. Applying philosophical concepts to society and politics was not unusual at the time, as seen in the works of Kant, Fichte, and Hegel. Yet, most of Mesmer’s contemporaries found his ideas too shaky, both medically and philosophically, to accept. Aside from a few stubborn followers, his theories were rejected by the medical sciences and not embraced by what we would now call the social sciences.

Notably, Mesmer was not alone in overextending the implications of medical theories into psychiatry. Similar tendencies to expand psychiatric concepts into broader worldviews are found in key figures like J. C. A. Heinroth, E. Kraepelin, E. Bleuler, and S. Freud. Even today’s debate about whether rapidly growing neuroscience knowledge should lead to a “new concept of humanity” falls within this context, a topic that will be addressed later.

Mesmerism

“Mesmerism,” in its popular form, with transitions into quackery that Mesmer himself did not endorse, became a fashionable trend in European cities, especially Paris, Vienna, and Berlin. From a psychiatric history perspective, Mesmerism presents itself as a system that aligned itself with the Enlightenment but leaned more toward natural-philosophical speculation. It can be seen as a precursor to modern methods of auto- and heterosuggestion, such as autogenic training and hypnosis. However, Mesmer’s rigid adherence to the letter of his original concept significantly hindered objective study of the phenomena he described, particularly suggestion (Darnton 1968; Hoff 1989a).

The Concept of “Romantic Psychiatry”

Authors mainly from the German-speaking world sought to distance themselves from Enlightenment rationalism, and they are now regarded as representatives of “Romantic Psychiatry.” As with all scientific and historical terms, caution is necessary: there was no singular “Romantic Psychiatry,” and not all psychiatrists associated with this movement shared the same theoretical or clinical views. The theoretical debate in early 19th-century psychiatry did not merely revolve around the often oversimplified and misrepresented conflict between the “psychic” and “somatic” schools. Nevertheless, the term “Romantic Psychiatry” is justified and serves as a useful guide for historical psychiatric research.

The Romantic spirit was expressed widely in society, especially in the arts, such as Romantic painting, music, and poetry, and initially had no direct connection to psychiatry. However, this link emerged almost naturally because the Romantics were fascinated by emotions, the incomprehensible, and the mysterious—what Ricarda Huch (1920) called the “dark side of the soul.” Many of the experiences and behaviors associated with these interests were and are particularly evident in people with mental disorders.

Heinroth and Ideler

Key psychiatric authors of this era, who can be labeled as “psychic” theorists, were J. C. A. Heinroth (1773–1843) and K. Ideler (1795–1860). Their writings include excellent psychopathological descriptions, driven by a genuine interest in individuals experiencing psychological distress, which remains evident even after nearly 200 years. Heinroth also developed a model of the psyche that strikingly resembled later psychoanalytic concepts, distinguishing between “instincts,” “consciousness,” and the “super-self.”

However, their psychopathological findings were often intertwined with speculative natural-philosophical or moral-religious contexts. Severe mental illnesses, for instance, were interpreted as consequences of a misguided lifestyle or “sinful behavior” (Cauwenbergh 1991; Heinroth 1818; Schmidt-Degenhard 1985).

The idea of personal responsibility for one’s life, and thus to some degree for one’s own illnesses, played a central role in the thinking of Romantic psychiatrists. For Heinroth, this led to a radical forensic consequence: if someone committed a crime during a severe mental disorder, they might not have known what they were doing at the moment, but they were still responsible. This was because falling into psychosis could be (at least partially) attributed to reproachable misconduct. This recalls the much later, controversial, and mostly rejected concept of “lifestyle guilt” in forensic literature, though it was not directly applied to the legal responsibility of individuals with psychosis.

Pioneering Role of Romantic Psychiatry

Despite the often linguistically based strangeness of some Romantic psychiatrists’ beliefs, recent research has shown that the broad disqualification of this psychiatric era—common especially towards the end of the 19th century, and still encountered today—is unfounded. This is aside from its, albeit debated, pioneering role for later psychodynamic and specifically psychoanalytic approaches.

Other important authors of this period include Johann Reil (1759–1813), who not only introduced the term “psychiatry” (originally “psychiaterie”) but also, in his theory of “common feelings,” developed a foundation for understanding psychotic disorders that remains relevant today. Ernst von Feuchtersleben (1806–1849) created psychotherapeutic and psychoeducational treatment forms, and Carl Gustav Carus (1789–1869) considered the “unconscious”—a term he used decades before Freud—to be a central, though partly unknowable, force in the realm of the psyche.

From Griesinger to “Brain Psychiatry”

Around the 1830s, a counter-movement began that aimed to align psychiatric research with the rising “positive” natural sciences. This complex development should not be confused with the previously discussed controversy between the Romantic schools of “psychics” and “somatics.”

A prominent figure in psychiatry at that time, Wilhelm Griesinger (1817–1868), was the most influential advocate for the idea that clinical psychiatry should address the mind-body problem empirically, not metaphysically, and should therefore engage in psychophysiological research. The well-known, though often misrepresented and oversimplified quote, “mental illnesses are brain diseases,” is the most concise expression of Griesinger’s carefully thought-out concept, which did not reduce clinical diagnostics to a simplistic “brain mythology.”

Psychiatry as an Empirical Science

Griesinger, who, according to Ludwig Binswanger, “gave psychiatry its constitution,” opposed any kind of uncritical speculation, whether nature-philosophical, romantic, or materialist. His main goal was to establish psychiatry as an independent, empirically working science committed to medical ethics, taking mentally ill individuals seriously as persons. His approach to psychiatry was both a predominantly biological research program and an applied medical anthropology.

Materialism

It is not entirely wrong, but can be misleading, to call Griesinger a materialist without reservation. The crucial point is that his materialism was methodological, not metaphysical. This connected him with the then-influential philosopher F. A. Lange (1828–1875). The central idea of this methodological materialism was the – compared to the uncompromising materialists of the late 19th century – rather modest thesis that, given the circumstances, a focus on the cerebral substrate, and thus a “materialistic” research approach, was scientifically the most promising. And if the mental was seen as a “function” of the neurobiological substrate but also as an independent phenomenon, not fundamentally denied, then – the declared goal of psychiatric research since Griesinger – the mental would also become accessible to empirical-quantitative research. Thus, it would no longer remain, as w

ith some romantic psychiatrists, especially those somatically inclined, isolated behind terms like “holy” or “divine” (Verwey 1985; Wahrig-Schmidt 1985).

Course Aspect of “Madness”

Not only this roughly outlined research program but also a psychopathological concept, namely the idea of “unitary psychosis,” developed together with his mentor Albert Zeller, director of the institution in Winnenthal, linked Griesinger’s name from the publication of his main work, Pathology and Therapy of Mental Disorders (1845, 2nd ed., 1861), with the fundamental issues of psychiatric nosology (Berrios and Beer 1995; Crow 1990; Mundt and Sass 1992; Rennert 1982). Even before Kahlbaum and Kraepelin, the course aspect was appreciated as a factor that differentiated and ordered any purely symptom-oriented nosology. However, Griesinger was not concerned with splitting into individual disease entities; rather, he sought to present “madness” as a single disease (unitary psychosis) that lawfully progresses through multiple stages (Vliegen 1980): primarily an affective disorder, then a delusional derailment (“insanity”) with paranoid-hallucinatory and, at most, catatonic symptoms, and finally, if no stagnation or remission occurs, a severe and irreversible deficit at the cognitive and behavioral level, termed dementia in today’s language.

However, Griesinger later – not dogmatically – accepted Snell’s description of “primary insanity” (1865), which did not require an affective preliminary stage, and thus revised his earlier concept. This debate is far from being merely of historical interest. The question of what type of illness or even disease entity we are dealing with in psychiatry, whether we speak of distinct categories or overlapping dimensions, remains a controversial topic in both current and future discussions.

City Asylums vs. Large Clinics

Griesinger was deeply involved in “social psychiatry,” to use a modern term. He clearly distanced himself from the views of Roller, head of the Badische Anstalt Illenau. Roller argued that mentally ill patients should be treated in secluded, rural facilities, separate from other patients. Griesinger, however, advocated integrating psychiatric care into general medical services. Specifically, he proposed the establishment of so-called “city asylums” (Griesinger’s term) for acutely ill patients needing short-term treatment. According to Griesinger, these “community-based” facilities should be linked with general city hospitals, as close coordination between referrers, clinics, follow-up care, and the patient’s living environment was essential for prognosis (Bergener 1987; Rössler 1992).

The second half of the 19th century saw the foundation of many large psychiatric clinics, usually located outside major urban areas, contrary to Griesinger’s intentions (Jetter 1981). Regardless, during this period, chairs for psychiatry or nervous diseases were established at most medical faculties.

Advances in Natural Sciences

During this time, the natural sciences, including biology, progressed rapidly. Advances in neuroanatomy, especially in understanding the cerebral localization of functions like motor skills, sensation, language, and memory, became particularly significant for psychiatry. This field was notably advanced by new techniques, such as the microtome designed by Bernhard von Gudden (1824–1886) for making very thin brain slices, and more specific histological staining methods like Franz Nissl’s (1860–1919) “Nissl staining.”

Unreflected Materialism

However, this progress was accompanied by some authors’ tendency to overextend the newly established neurobiological paradigm and promote a barely reflected materialism. For authors like the Viennese psychiatrist Theodor Meynert (1833–1892), mental, especially psychotic disorders, were simply “diseases of the forebrain,” as indicated by the subtitle of his influential 1884 psychiatry textbook. Contemporary and later critics not unjustly labeled late 19th-century (university) psychiatry as “brain psychiatry,” “psychiatry without a soul,” or, mockingly, as Jaspers did, “brain mythology.” Despite the now-strange terminology, the parallels between the fundamental questions of the field then and today in the 21st century are striking. These include the connection between subjectivity and brain function or the concept, if not the “essence,” of mental illness itself (Kronfeld 1920). This topic will be revisited.

Theory of Degeneration
The “degeneration theory” was not just a topic debated among psychiatric specialists. It significantly shaped the intellectual profile of the late 19th and early 20th centuries through literature, natural sciences, and even politics (Chamberlin and Gilman 1985; Pick 1989; Wettley 1959). The part of this theory most relevant to psychiatry drew key impulses from French psychopathology, particularly from B. A. Morel (1857) and V. Magnan (1896). The approach assumed that a gradual “mental degeneration” could manifest over generations within a family, ranging from mild psychological traits like nervousness or reduced resilience, through marked affective disorders and psychotic episodes, to severe dementia (Hermle 1986; Liegeois 1991).

Psychiatric degeneration theorists, such as H. Schüle and R. von Krafft-Ebing in the German-speaking world, relied on extensive observations and supported their empirical data with a theory that was partly scientific (Magnan) and partly moral-philosophical (Morel). Other authors, especially from the Italian criminal anthropology school led by Cesare Lombroso, directly linked the theoretical concept of degeneration with empirical evidence. They emphasized the diagnostic, even prognostic value of physical traits (“stigmata”), from which they inferred both psychopathological connections and the degree of “degeneration” reached (“the born criminal,” Lombroso 1887).

Degeneration Theory and Racial Theory

The basic ideas of degeneration theory appear in almost all psychiatric or neurological textbooks around the turn of the century, often in more or less clear forms. For example, Emil Kraepelin, a particularly influential psychiatric author, will be mentioned again in another context. This example demonstrates both the widespread acceptance of degeneration theory and the – for today’s readers, unsettling – ease with which its terminology was considered scientifically acceptable, even necessary.

It is important to handle this historically significant and emotionally charged topic with care. Not every turn-of-the-century author who used the language of “degeneration theory” can be automatically discredited as a direct precursor or supporter of Nazi terror against the mentally ill.

Nevertheless, degeneration theory and National Socialism are interconnected through the concepts of Social Darwinism and “racial hygiene” (see below), making the situation highly complex. While there is certainly no simple cause-and-effect relationship here, the scientifically weak degeneration theories helped pave the way for even more speculative, absurd racial theories.

Nevertheless, degeneration theory and National Socialism are interconnected through the concepts of Social Darwinism and “racial hygiene” (see below), creating a complex intellectual history. There is certainly no simple cause-and-effect relationship, but the scientifically shaky degeneration theories made it easier for the Nazis’ even more speculative, absurd racial theories to disguise their ideological distortions as scientific.

Use of the Degeneration Concept in Kraepelin’s Example

Many turn-of-the-century psychiatrists, including Emil Kraepelin, frequently used the concept of degeneration. Kraepelin, far from being an apolitical scientist (Engstrom 1991), often referred to “degeneration,” “the degenerate,” “degenerative basis,” and “inferiority.” This was particularly evident in his descriptions of what we would now call personality disorders, as well as dysthymic or sexually deviant individuals. However, it would be wrong to conclude that German-speaking psychiatry around 1900 had an entirely uncritical attitude toward degeneration theory. Especially after the “rediscovery” of Mendel’s laws of inheritance, the vague concept of “degeneration” began to lose ground. For instance, Kraepelin’s extensive use of degeneration theory contrasted oddly with his frequent criticisms of its conceptual vagueness. He spoke of the “uncertain and fluctuating boundaries” of the concept of degeneration (Kraepelin 1915, p. 1973). In 1918, he rejected the comprehensive explanatory claims of the theory as proposed by Magnan: Even though, as Kraepelin noted, “through [Magnan’s] efforts to fundamentally oppose the mental disorders of the degenerate to those of the healthy disposition… the close relationships of certain forms of insanity to hereditary predisposition were clearly highlighted, the sharp division between these two groups proved unfeasible” (Kraepelin 1918, p. 253).

Differentiation Between “Healthy” and “Ill”
Kraepelin’s use of terms like “hereditary degeneration,” “morbid disposition,” “mental developmental hindrances,” or “congenital conditions” was far from consistent. Sensing this inconsistency, he relied on a quantitative approach when differentiating between “healthy” and “ill,” especially for non-clearly psychotic disorders. This was primarily based on severity, particularly in terms of the psychosocial impact of a mental disorder:
“If, in the strictest sense, we were to consider all congenital traits that hinder the attainment of general life goals as manifestations of degeneration, we would find such traces everywhere. However, we can only attribute the significance of pathology to personal deviations from the prescribed direction of development when they significantly impact physical or mental life; thus, the distinction is purely gradual and, to some extent, arbitrary” (Kraepelin 1915, p. 1973).

Ethical Considerations
Consistently, Kraepelin repeatedly warned against the careless implementation of such concepts into concrete actions. For example, he was skeptical of the American practice he mentioned, where sterilization was performed for certain mental disorders, citing the unavoidable ethical dilemma:
“Without doubt, the measure would be effective, but determining where to draw the line would be difficult” (Kraepelin 1903, p. 386).

Genetic Factors vs. Personality and Environment
Heimann (1989) pointed to another example of a willingness to critically assess degeneration theory. In July 1920, during a meeting of the German Research Institute for Psychiatry led (and founded) by Emil Kraepelin, the future Tübingen Professor of Psychiatry and staunch Nazi, H. F. Hoffmann, spoke about his ideas on racial hygiene and hereditary biology. Despite generally supporting genetic research in psychiatry, Kraepelin expressed significant concerns about making uncritical inferences from symptoms to underlying disease processes. He emphasized that “the disease” does not directly lead to clinical symptoms. Instead, personality and environment—factors not necessarily linked to heredity—are of notable importance.

Degeneration Theory as a Conceptual Background
For Kraepelin, the degeneration theory served as a broad but not dogmatically applied framework. It was the conceptual background for understanding various mental disorders (Hoff 2008). It had the least impact on Dementia praecox (schizophrenia) but was most evident in manic-depressive illness, paranoia, and personality disorders.
Despite generally supporting the concept of degeneration, Kraepelin clearly rejected biological reductions, such as the idea of “stigmata degenerationis.” His stance, and that of other contemporary authors, remained ambiguous on key issues, such as the relationship between the neural and mental levels (“mind-body problem”) or other scientific-theoretical questions. Although Kraepelin extensively discussed these issues in all editions of his textbook and a separate study dedicated to the topic (Kraepelin 1908), his views remained unclear. In the German-speaking world, Bumke’s study “On Nervous Degeneration” (1912) is considered the decisive critique of the traditional form of degeneration theory.

Clinicians at the Turn of the 19th to 20th Century
Clinical-Pragmatic Course Research
Parallel to the development of the degeneration concept, and sometimes significantly influenced by it, clinical-pragmatic course research came to the forefront, following the studies of Wilhelm Griesinger and Karl Ludwig Kahlbaum (1828–1899). With Emil Kraepelin (1856–1926), this approach gained prominence. Kahlbaum and Kraepelin found earlier classifications unsatisfactory, particularly because they gave too much weight to fluctuating clinical states rather than the long-term course of illness. Both authors can be called “pragmatic” because they sought comprehensive and precise clinical descriptions of disease courses, using this empirical knowledge to develop theoretical-systematic ideas. Particularly in Kraepelin, there was a marked skepticism toward deeper scientific-theoretical considerations in psychiatry. Kahlbaum, on the other hand, created a theoretically complex nosological system, which later fell into obscurity and is not discussed here. Clinically, Kahlbaum is best known for describing catatonia, which he called “tension insanity” (Kahlbaum 1874; Lanczik 1992).

Emil Kraepelin
Emil Kraepelin continued aspects of the clinical research initiated by Griesinger and Kahlbaum but strongly shaped it with his own concepts. Like Kahlbaum, Kraepelin frequently criticized, even disparaged, the purely symptom-based approach to psychiatric diagnosis common among many 19th-century authors. While he acknowledged that Griesinger had emphasized the course aspect, Griesinger’s concept of “unitary psychosis,” which was previously discussed, did not convince the pragmatic clinician Kraepelin. The key to the lasting influence of Kraepelin’s work was likely that he provided psychiatry, which was struggling with the terminological confusion of the 19th century, with a nosological reference system. This system was based on decades of clinical experience, was legitimized “within psychiatry” (not philosophically or neuroanatomically), and was prognostically and pragmatically oriented.

Concept of “Natural Disease Entities”
Against the background of the degeneration theory, which he largely but not uncritically accepted, Kraepelin built his approach on psychophysical parallelism, strict (though rarely discussed) philosophical realism, and a firm focus on observable clinical reality. These were the foundations that enabled Kraepelin to effectively align different methodological approaches towards a common research goal: identifying what he called “natural disease entities.” The central hypothesis of this approach is that, as in other medical fields, psychiatry has naturally given – in modern terms, biological – disease entities that exist exactly as they are, independent of who suffers from them or whether they are studied.

According to Kraepelin, these entities are not “constructed” by psychiatrists; they are not mere psychopathological conventions but objectively existing and clearly distinguishable entities, similar to objects in the external world, like different plant species. Kraepelin’s far-reaching postulate was that, regardless of the research method – whether pathological anatomy, etiological-pathogenetic research, or symptomatology including disease course – psychiatric researchers, with sufficiently refined techniques, will necessarily move towards discovering the same nosological entities: the “natural disease entities” that exist prior to any research.

Psychiatric Research and Scientific Theory
Kraepelin was, of course, aware of the high standards he was setting for psychiatric res

Alfred Erich Hoche
A significant alternative to Kraepelin’s understanding of psychiatry was presented by Alfred Erich Hoche (1865–1943), a figure of historical importance in psychiatry. In this context, Hoche’s persistent criticism of Kraepelin’s concept of “natural disease entities” is relevant. Hoche found it too speculative, or at least premature. He spoke of the “hunt for the phantom” of disease entities and mocked Kraepelin’s numerous small and large adjustments to nosological boundaries, saying that one does not clarify a murky liquid—namely, the clinical picture and course of mental disorders—by pouring it from one container to another, i.e., merely giving the disorders new names (summarized in Hoche 1912).

Hoche proposed setting aside the question of natural disease entities as either temporarily or fundamentally unanswerable. Instead, he advocated for the development of empirically supported symptom complexes, which would be fully sufficient for practical and research purposes. This approach, later known as “syndromal,” became widely accepted, though it does not necessarily exclude the existence of disease entities “behind” the syndromes. It is worth noting that Hoche was one of two authors of a 1920 book that discussed and definitively endorsed the “killing of lives unworthy of living” from a legal and psychiatric perspective (Binding and Hoche 1920). This topic will be revisited.

Robert Gaupp and Ernst Kretschmer
Some other important conceptual contributions that emerged in the early 20th century should be mentioned: Robert Gaupp (1870–1953), who was Kraepelin’s senior physician in Munich until 1906, and Ernst Kretschmer (1888–1964), both from Tübingen, developed a psychopathologically grounded approach that, in some respects, distanced itself from Kraepelin’s thinking, though not fundamentally.

Understanding Approach to the “Unintelligible” in Delusions
Gaupp was mainly concerned with the question of whether an understanding approach, emphasizing biography and personality development, could, at least in individual cases, make the “unintelligible” in delusions comprehensible. He viewed delusions as psychologically understandable, albeit unusual, reactions to specific configurations of psychological, social, and physical conditions. Gaupp developed this theme masterfully using the case of “Head Teacher Wagner,” whom he examined. Wagner, driven by psychotic experiences, killed his family and several bystanders and committed arson in 1913. Gaupp maintained contact with Wagner until his death in 1938 and published numerous works on this case (Gaupp 1920). Neuzner and Brandstätter (1996) comprehensively analyzed Wagner’s case history, focusing on his long relationship with Gaupp and his plays and other literary works.

Constitutional Biological Approach
This line of research was complemented and significantly expanded by Gaupp’s student Ernst Kretschmer. Notably, his monograph on Sensitive Delusional Disorder (1918) stands out in this context. Kretschmer adopted a constitutional biological approach, attempting to link specific physical traits, especially body type, with psychological characteristics and disorders, potentially even establishing a causal relationship. Kretschmer called for a “multidimensional” diagnostic approach, which resonates with modern diagnostic methods, including comprehensive assessments.

Carl Wernicke, Karl Kleist, and Karl Leonhard

The prominent clinician and researcher Carl Wernicke (1848–1905) developed a psychiatric system that, in many ways, viewed the endogenous psychoses as analogs of neurological systemic diseases. He focused intensely on psychotically disturbed motor expression, especially catatonic symptoms. The school he founded was continued by Karl Kleist (1879–1960) and Karl Leonhard (1904–1988). These authors, moving beyond Kraepelin’s division, which they considered too coarse, and rejecting his nosological dichotomy of endogenous psychoses, defined distinct mental disease entities. These entities were sharply differentiated regarding their genesis, familial burden, symptomatology, course, and therapy. Karl Leonhard elaborated on this concept most clearly in his classification of endogenous psychoses (1980). This approach represents the opposite of Griesinger’s and Rennert’s unitary psychosis concept.

Karl Bonhoeffer
Karl Bonhoeffer (1868–1948), who was director of the Clinic for Mental and Nervous Diseases at Berlin’s Charité for 26 years after his time in Breslau (1912–1938), proposed the “nosological nonspecificity” of psychopathological symptoms. He established the still-accepted thesis that the brain has only a limited number of response possibilities to a theoretically unlimited number of noxae. This renders any direct conclusion from symptom to cause invalid (Bonhoeffer 1910).

Eugen Bleuler
The Swiss psychiatrist Eugen Bleuler (1857–1939) was one of the few university psychiatrists who tried to integrate Freud’s psychoanalysis into clinical psychiatry. However, later, after increasing conceptual discrepancies between Bleuler’s and Freud’s core beliefs emerged, he distanced himself from this position, though not completely (Bleuler 1913; Küchenhoff 2001). After a critical review of existing research, Bleuler suggested, following a 1908 lecture (Maatz and Hoff 2014), that instead of Kraepelin’s term “Dementia praecox,” the heterogeneous symptomatology, and possibly etiological-pathogenetic differences, warranted referring to the “group of schizophrenias” (Bleuler 1911). This suggestion gained wide acceptance.

Bleuler’s distinctions between basic symptoms and accessory symptoms, as well as between primary and secondary symptoms, became significant for the systematic classification of psychopathological phenomena. Basic symptoms were present in every case of schizophrenia, while accessory symptoms might, but did not have to, be present. The second distinction was etiological: primary symptoms directly resulted from the neurobiological disease process, which Bleuler also suspected, while secondary symptoms were the patient’s psychological reactions to the illness. Bleuler’s contributions to understanding the course of schizophrenic disorders were pioneering, as he moved away from Kraepelin’s pessimistic view of the necessarily poor outcome of “Dementia praecox” and described groups of patients who partially or fully remitted.

Christian Scharfetter (2006) has provided a comprehensive and critical assessment of Bleuler’s work from a psychopathological and scientific-theoretical perspective. The volume also contains a historically significant text by Manfred Bleuler (1903–1994), son and (not direct) successor of Eugen Bleuler as head of Zurich’s university clinic “Burghölzli.” Recently, there has been a notable increase in scientific interest in “classic” historical psychiatric positions, including those of Eugen Bleuler.

Psychoanalysis and Behaviorism
Psychoanalysis
Sigmund Freud’s (1856–1939) research interest initially, and later more implicitly, focused on neurophysiological connections (Hirschmüller 1991; Hoffmann-Richter 1994; Miller and Katz 1989; Sulloway 1983). After working with Brücke and Meynert in Vienna, he was deeply impressed by the influence of suggestion and hypnosis on psychological phenomena, especially hysterical symptoms, which he observed in Paris under J. M. Charcot (1825–1893). Together with J. Breuer (1842–1925), Freud developed a treatment strategy for hysterical disorders, which can be seen as a precursor to the later “psychoanalytic cure” in a narrower sense.

Theory of Psychoanalytic Treatment
The core of psychoanalytic theory is the concept of an unconscious psychological domain that significantly affects conscious experience. This can have negative effects, especially when an unresolved unconscious conflict—the key concept in psychoanalytic neurotheory—becomes overwhelming. Its pressure to surface in conscious perception can lead to distress and symptoms. Through the “royal road” of dream interpretation, as Freud called it, a sustainable access to unconscious content is possible in psychoanalytic treatment. By reliving conflicting moments within the therapeutic relationship with the analyst, through “transference” in a cathartic process, these conflicts can be brought to awareness and moved closer to resolution, ideally even fully resolved.

Psychic Structures
Freud later expanded this therapy-oriented model with the concept of different psychic structures, which applied to both disturbed and healthy minds. These included the “Id,” containing instincts and drives; the “Superego,” representing all kinds of norms; and the “Ego,” the interface relevant for the individual’s experience and actions, and thus the “site” of potentially autonomous decisions.

Rejection by Academic Psychiatry
Contemporary academic psychiatry largely rejected psychoanalysis, with few exceptions—the most prominent being the Zurich psychiatrist Eugen Bleuler. Psychoanalysis was not accepted as either a therapeutic method or a worldview. A sharp example of the majority’s biting and polemical rejection was Emil Kraepelin, who saw psychoanalysis as a psychological speculation that lost itself in individual arbitrariness and overemphasized the sexual domain. This strong rejection, especially by neurobiologically oriented authors, is remarkable, as Freud always considered himself a natural scientist, albeit in a very specific sense. Originally, like most research-oriented psychiatrists of the late 19th century, he was guided by the prevalent goal of achieving a physiological or biochemical understanding of psychological phenomena. However, he came to the reasonable conclusion that, with the research methods available at the time, these questions could not yet be adequately answered on what we would now call a neuroscientific basis. Thus, as an unavoidable preliminary stage, a systematic psychological approach was needed—psychoanalysis.

Psychoanalysis and “Romantic Psychiatry”

The complexity of the literature on the scientific classification of psychoanalysis stems partly from the fact that Freud’s scientific drive was not recognized or acknowledged. Additionally, there are indeed parallels between the psychoanalytic view of humanity and that of “romantic psychiatry.” This is especially true regarding the emphasis on individual life history and the affective side of the psyche. A notable conceptual closeness between the thoughts of Heinroth and Freud has been highlighted multiple times, and some have seen Heinroth and the late romantic author Carl Gustav Carus (1789–1869) as direct, though unacknowledged, precursors of psychoanalysis.

Discrepancy Due to Different Languages
The psychoanalytic concept of illness focused on the aspect of individual psychological development, which could be hindered or fail at any stage. However, this did not exclude the importance of somatic factors. The growing discrepancy with academic psychiatry resulted, not least, from the fact that “psychodynamic languages” emerged, which were not compatible, either in terms of specific terminology or developmental and personality-psychological assumptions, with a clinical psychiatry like that of Kraepelin (Hoff 2006). Kraepelin’s successors at the Munich chair, O. Bumke and K. Kolle—neither of whom were uncritically positive about Kraepelin’s understanding of psychiatry—continued his tradition of largely uncompromising criticism of psychoanalysis. Bumke (1926) expressed persistent doubts about the concept of the “unconscious” in a well-defined argument. This work is of particular interest for the later debate on the scientific status of psychoanalysis, especially initiated by A. Grünbaum (1987).

Behaviorism
An approach largely opposite to the psychoanalytic perspective was represented by behaviorism, founded by J. Watson at the beginning of the 20th century. Here, the focus was on observable (and thus measurable) behavior and its modification through psychotherapy, rather than on unconscious conflicts, which are accessible only through subjective and intersubjective interpretation. Watson viewed phobic disorders, for instance, as conditioned, or “learned,” and proposed desensitization procedures for the phobic stimulus. Other important authors who established the behaviorist tradition, later known as behavior therapy, were E. L. Thorndike and B. F. Skinner.

Psychopathology: Karl Jaspers and the “Heidelberg School”
Explanation and Understanding
While Kraepelin’s philosophical assumptions about psychiatric practice were mostly overlooked, other contemporary authors focused decisively on methodological and theoretical problems in psychiatry. This shift was facilitated by the growing reception of the distinction between explanation and understanding, emphasized by the German philosopher W. Dilthey, based on the work of historian Droysen, in psychiatric literature around the turn of the 20th century. Among the dense monographs dealing with this topic and the systematic presentation of the conceptual foundations of psychiatry are Karl Jaspers’ General Psychopathology (1913), Ernst Kretschmer’s The Sensitive Delusion (1918), and Arthur Kronfeld’s The Nature of Psychiatric Knowledge (1920), despite their differences. Only Jaspers’ book, which had a particularly strong and lasting impact on the scientific discourse, will be discussed here.

Karl Jaspers
Karl Jaspers’ goal was to establish psychopathology, which he considered the foundational science of psychiatry (as Janzarik later termed it in 1979), on a solid and thoughtful methodological basis, stripping speculative and dogmatic approaches of their credibility. In his book, he described individual psychopathological phenomena with great clinical precision, often supplemented by case studies, as well as the foundations of the undisturbed psyche.

Unknowability of Wholeness
Jaspers insisted that the clear understanding of the whole of a mentally healthy or disturbed person, especially in their biographically developed uniqueness and personality, could not be fully achieved by any scientific method. A method must recognize not only its possibilities but also its limits. Overreach would inevitably lead to dogmatic rigidity, which Jaspers masterfully illustrated using various types of psychiatric biases (Hoff 1989b). He criticized the unreflective identification of neuroanatomical or neurophysiological findings with psychological experience, mockingly calling it “brain mythology,” as well as metaphysical speculations about the origin and nature of mental disorders that were clinically unconvincing.

Observability of the Psychological
Jaspers maintained that psychological phenomena can never be directly observed as such, unlike physical natural processes (at least at first approximation). Instead, they can only be perceived through the expressions of the experiencer, such as their language, facial expressions, and gestures—in short, in intersubjective encounters, including artistic works. His differentiation of static and genetic understanding from scientific explanation, which extended beyond Dilthey’s concepts, became highly significant.

Jaspers extensively revised and expanded the General Psychopathology text several times, most recently during World War II. In the later editions, the perspective of his own (existential) philosophical position became more pronounced. Many authors rightly regard Jaspers’ book as the true beginning of methodologically reflective psychopathological research; it is unquestionably one of the most influential texts in psychiatry. Jaspers’ significance as a historian of psychiatry, pathographer, and existential philosopher is noted here. Bormuth (2002) provides information on his critical stance towards psychoanalysis and its cultural-historical context.

Heidelberg Psychiatry
In the tradition of Heidelberg psychiatry, prominently represented in the IX. (Schizophrenia) volume of Bumke’s Handbook (1932), one can most clearly see the continuation of Kraepelin’s ideas. For instance, W. Gruhle, in his historical contribution, highlighted that the “purely functional view of the soul” rooted in the “Kraepelinian tradition of pure observation” had “no precedent in the history of psychiatry” (Gruhle 1932). This purely functional psychopathology (note: today the term “functional psychopathology” is often used differently) focused less on the content (the “being-so”) than on the factual existence of phenomena like delusions (the “being-there”), contrasting with Bleuler’s concept of schizophrenia. Despite a balanced and nuanced discussion of methodology, Gruhle made it clear “that there is no doubt in this volume about schizophrenia as a process of destruction, nor about manic-depressive insanity as not merely a symptom complex but a disease entity” (Gruhle 1932).

Kurt Schneider
Kurt Schneider (1887–1967) also stands in the tradition of Heidelberg psychiatry, being an essential part of that tradition himself (Huber 1997; Janzarik 1984). To avoid confusion with Carl Schneider, one of the central figures in Nazi psychiatry, it is important always to include Kurt Schneider’s first name.

Pathogenesis: Karl Schneider’s Somatose Postulate
K. Schneider adhered to a long-standing view in German-speaking psychiatry that endogenous psychoses are ultimately organic disorders of the central nervous system. This perspective is known as the “somatose postulate.” However, Schneider, known for his style of methodical critique and scientific purism, emphasized that this was a model, a postulate, or, as he called it, a “heuristic principle,” which did not fundamentally exclude other modes of origin for mental, including psychotic, disorders. He explicitly acknowledged “the third possibility alongside the somatogenic and psychogenic: the metagenic, a deviation of the soul without somatic or psychological cause,” although he did not elaborate on this concept.

Descriptive Psychopathology
Methodical critique and self-restraint were also guiding principles in K. Schneider’s main work, Clinical Psychopathology, which reached its 15th edition in 2007. Despite differences in theoretical approach and purpose, this text’s logical rigor and influence on future developments make it comparable to Jaspers’ General Psychopathology. Against the background of his medical and philosophical training, Schneider developed a mainly descriptive psychopathology that did not atomize the psyche but maintained a clinically meaningful, holistic understanding.

A hallmark of his work was his effort to establish precise psychopathological terminology, which led to the identification of “first-rank symptoms.” In the absence of detectable brain-organic disorders, he “humbly” recommended using the term schizophrenia when these symptoms were present.

Psychiatric Diagnoses as Adaptable Constructs
For Schneider, psychiatric diagnoses were far from merely replicating what Kraepelin described as “natural disease entities.” Instead, he viewed them as provisional, conceptually grounded constructs that needed to undergo a constant process of adaptation and renewal, guided by empirical knowledge and conceptual development. This nominalist perspective on psychiatric diagnoses, which contrasted with Kraepelin’s pursuit of real definitions, and the demand for clear and universally accepted diagnostic criteria, positioned K. Schneider as a key precursor to modern operationalized psychiatric diagnostics, such as the ICD-10 by the World Health Organization (WHO 1991) and the DSM-5 by the American Psychiatric Association (APA 2013).

Psychosomatic Medicine
The term “psychosomatic medicine” has numerous historical and conceptual roots. It is still used with such varying meanings that a concise definition is not possible. The following connections are of particular importance in the historical context of psychiatry. The earliest explicit use of “psychosomatic” appeared in the context of early 19th-century romantic psychiatry, for instance, in Heinroth’s works (1818). In internal medicine, there were intensive discussions on this topic during the first half of the 20th century, notably in Viktor von Weizsäcker’s concept of the “Gestalt circle,” which targeted both scientific and clinical areas (Benzenhöfer 2007; Weiner 2008).

Originally conceived as a counterpoint to the dualistic position that tried to strictly, even categorically, separate the somatic from the psychic, the scope of “psychosomatic” broadened over time. It became similar to, or even synonymous with, “psychogenic,” was associated with hysterical expressions, described illnesses with physical complaints where no (clear) somatic findings could be made, or encompassed certain internal conditions where psychological and social factors were seen as decisive for the origin and course alongside somatic (e.g., genetic) predispositions, such as asthma, hypertension, or ulcerative colitis.

In recent decades, the self-concept of the psychosomatic field has moved away from these narrow definitions. A developing “psychosomatic perspective” (Kapfhammer 2000) has been both distinctly practice-oriented, promoting interdisciplinary collaboration in consultation and liaison psychiatry, and theoretically focused on a foundational stance that emphasized the importance of a person-oriented integration of somatic, psychopathological, and social aspects in all medical disciplines. This modern approach revisits the core motives of pioneering figures in early psychosomatic medicine.

From Degeneration Theory to Racial Hygiene and Psychiatry under National Socialism
Having connected to the current situation of psychiatric care and research at the end of the previous section, a step back in time is now necessary to understand the background of the darkest chapter in German psychiatric history: the Nazi perversion of neuropsychiatric theory and practice.

Social Darwinist Thinking
Long before 1933, certain racist, social-political, and ideological conflicts and polarizations had begun. As previously mentioned, since the late 19th century, there was a broad consensus across European societies that part of the population was inferior, degenerate, and genetically burdened. They were seen as social burdens, contributing nothing useful to society, yet reproducing faster than the elites. This social Darwinist thought, closely tied to degeneration theory, led to the idea of “selecting” one group while “eliminating” the other to sustainably improve, even “save,” society. The term “racial hygiene” was coined by Alfred Ploetz in 1895. This also includes the concept of “eugenics,” which referred to controlled reproduction based on genetic theories. This thinking tragically merged with antisemitism, as countless Jewish doctors experienced firsthand. For instance, the geneticist and psychiatrist F. J. Kallmann had to leave Germany in 1936. He went on to establish a highly influential genetics department at the Institute of Psychiatry in New York.

No Consensus Among Psychiatrists
On January 1, 1934, the “Law for the Prevention of Hereditarily Diseased Offspring,” passed on July 14, 1933, came into effect. Despite claims by genetic researchers and racial hygienists, there was no universally accepted psychiatric system. Genetic research was on shaky ground, especially regarding the diagnostic classification of illnesses. Knowledge of the diverse causes of congenital intellectual disabilities was inadequate; it was often mistakenly equated with hereditary intellectual disability. Similar misunderstandings applied to various forms and causes of epilepsy, not to mention the brutal conclusion to control these and other conditions through “elimination” and forced sterilization (Holdorff and Hoff 1997; Weber 1993).

There was resistance from some in the psychiatric field against the regulations imposed by the Nazis. For example, K. Kleist and O. Bumke avoided using diagnoses that fell under the sterilization laws in their psychiatric departments or refrained from reporting them to the authorities.

Sterilization, Euthanasia, and Human Experiments
From voluntary sterilization, advocated by many in the 1920s and introduced as a bill in the early 1930s, the Nazis moved to forced sterilization and, with the outbreak of war, seamlessly to the “euthanasia program.” What initially suggested euthanasia for terminally ill people out of compassion and, at best, at their request, evolved into the killing of “inferior” individuals—”ballast lives” seen as burdens to society. The hypocritical term “mercy killing” was retained. A medicine with a narrow, biologistic view, which turned people into objects and labeled outsiders, homosexuals, the mentally ill, physically and intellectually disabled, and other perceived marginal groups as “inferior,” did not stop at human experiments. Such experiments were conducted not only in the extreme conditions of concentration camps but also in some “normal clinics,” where (forced) experiments were carried out on patients (Finzen 1996; Heimann 1989; Hulverscheidt and Laukötter 2009; Karenberg 2006; Lifton 1986; Reitzenstein 2014; Seidel and Werner 1991). These horrifying actions, which violated medical ethics, were a key driver for the post-World War II international efforts to establish binding frameworks for medical research involving humans, whether healthy or ill. The “Declaration of Helsinki,” adopted by the World Medical Association in 1964 and last updated in 2008, is the most prominent result of this process (Williams 2008, Sec. 2).

Opposition Doctors
During the Weimar Republic, there were still numerous critical movements against these extreme tendencies. They formed in outpatient clinics, preventive care, social hygiene, counseling centers for sexual health and sexually transmitted diseases, and groups like the Association of Socialist Doctors, which included many Jewish colleagues such as K. Goldstein. After 1933, this opposition within the medical community had no further influence and was suppressed, persecuted, expelled, or destroyed . The field of psychotherapy, where biologistic reduction was harder to argue than in the etiology and treatment of severe psychotic disorders, was also subject to the “coordination” of all medical disciplines during the Nazi era, as comprehensively detailed by Cocks (1985).

The Law for the Prevention of Hereditarily Diseased Offspring
The “Law for the Prevention of Hereditarily Diseased Offspring” mandated that all licensed doctors report the following conditions, designated as hereditary diseases: “congenital intellectual disability, schizophrenia, manic-depressive insanity, hereditary epilepsy, Huntington’s chorea, hereditary blindness, hereditary deafness, severe physical deformity, and severe alcoholism.” Despite significant resistance from some affected individuals and their families, about 360,000 people were sterilized under this law between 1934 and the end of the war. In Hitler’s Mein Kampf (1935 edition), this issue was addressed quite clearly: “Sterilization in such cases is the most humane act of humanity… It will spare millions of unfortunate people from undeserved suffering… The temporary pain of a century can and will redeem millennia of suffering.” (p. 279).

Disabled Children
Children also became targets of this destructive ideology: In August 1939, the Reich Ministry of the Interior issued a secret decree requiring the reporting of children with severe deformities and those with trisomy 21 (“Mongolism”). Based on available records—often just sparse reporting forms—three assessors decided the fate of each child, including whether they would be killed. From 1940 onwards, about 30 “children’s wards” were established, where an estimated 5,000 children were deliberately killed through the administration of morphine, barbiturates, or by starvation.

Murder of the Mentally Ill and Intellectually Disabled
With the start of the war, the wave of sterilizations transitioned almost seamlessly into the “T4 Action,” named after Berlin’s Tiergartenstraße 4, where key planning decisions were made. This represents the worst entanglement of psychiatry with Nazi crimes: Estimates suggest that during the “Third Reich,” especially in 1940 and 1941, between 80,000 and 130,000 mentally ill and intellectually disabled people were transported from clinics to extermination centers, where most were killed in gas chambers. Under the “T4 Action,” all patients who were not able to work or could only perform simple mechanical tasks were to be reported if they suffered from conditions like schizophrenia, epilepsy, senile diseases, therapy-resistant paralysis, other syphilitic disorders, intellectual disability of any cause, encephalitis, Huntington’s chorea, and similar neurological conditions. Additionally, all individuals who had been institutionalized for more than five years were to be reported.

Legal Concept of the “Mentally Dead”
The Nazis could justify their actions partly by referring to a 1920 book written by jurist Karl Binding and psychiatrist Alfred Erich Hoche (mentioned earlier in a different context) titled Permission for the Destruction of Life Unworthy of Life. This work, published two decades before the Nazi killings, argued that severely chronically ill people, under certain conditions, were no longer to be considered human or persons, but rather as already dead, as “mentally dead,” as the text put it. The crucial and fatal step in the argument was the assertion that such a “non-person” could be biologically killed without it being considered manslaughter or murder. Killing a “mentally dead” individual was seen not only as non-punishable but also as necessary to prevent further individual suffering and—an aspect given great weight—to relieve society of “useless,” “life-unworthy” members. Remarkably, or rather distressingly, there was no significant debate within the psychiatric community of the Weimar era about this text (Meyer 1988). Later, however, the controversy over Hoche’s life and work became dominated by this issue (Schimmelpenning 1990; Seidler 1986).

Resistance
There was resistance to the killings from psychiatrists like Walther von Baeyer, Karl Kleist, and Kurt Schneider, as well as from affected families, the general population, and the churches; notably, Cardinal Graf von Galen from Münster. Due in part to this resistance, which could neither be completely suppressed nor kept secret, the killings of the mentally ill in gas chambers were halted in August 1941. However, the disorganized “euthanasia” continued through pseudo-scientific experiments, including starvation, medication administration, and artificially induced severe infections.

After World War II, the chief euthanasia assessors were brought to trial in the Nuremberg Trials, unless they had evaded justice by suicide (de Crinis 1945; Carl Schneider 1946) or by fleeing into anonymous illegality, as Heyde did. Werner Heyde was able to practice medicine and act as an expert witness for several years after the war under the pseudonym Fritz Sawade. After his discovery and imprisonment, he also committed suicide (1964).

The Need for Research
Fortunately, much research has been conducted on this darkest chapter of German psychiatric history in recent decades. However, the systematic and methodologically sound research only truly began more than 20 years after the war ended. The careful analysis of the intellectual development from the mid-19th century to 1933 and 1945, particularly regarding the emergence and differentiation of degeneration theory, Social Darwinism, and eugenics, remains an ongoing task. It is crucial to examine the patient records of psychiatric clinics and the archives of other institutions to a much greater extent than before. This will provide a more comprehensive and precise understanding of the historical facts and the theoretical concepts that made them possible.

The Second Half of the 20th Century
Historical Reappraisal
The Nazi perversion of psychiatric theory and practice left a heavy burden on post-war psychiatry in Germany. Initially, there was a need to document what had happened, later often labeled as “incomprehensible” and “unfathomable,” and to make historical facts accessible for scientific research. However, this process, as mentioned, began very slowly. It is important to note that entire research fields, particularly psychiatric genetics, had fallen into disrepute for decades and practically ceased to exist in the German-speaking world during this period. This has since changed, though awareness of the historical background should always remain present in current research.

Anthropological Psychiatry
In the 1950s, a branch of psychiatry called “anthropological psychiatry” gained significant influence. Unlike earlier concepts that often avoided engaging with their philosophical premises, this field openly embraced a specific philosophical approach—existential philosophy. Ludwig Binswanger’s existential analysis emphasized the existential, rather than merely psychological-hermeneutic, understanding of the individual in the genesis, manifestation, and treatment of mental disorders. This approach rejected elementarist psychology and focused on the wholeness of psychological acts and their structure. From this perspective, psychosis, especially in its delusional form, is seen as a distinct disorder characterized by a restriction in freedom of experience and action, a “loss of natural self-evidence,” and an “inability to shift perspectives” in one’s life (Binswanger 1965; Blankenburg 1971).

From Gestalt Psychology to Structural Dynamics
Psychology had long had an empirical tradition that also opposed an elementarist understanding of psychological phenomena. With the slogan “the whole is more than the sum of its parts,” this approach emphasized personal wholeness while still recognizing its internal differentiation—not into additive elements, but into complex structures that are not sharply separated at the edges. This “Gestalt psychology,” originally from perception research, entered psychiatry primarily through the work of Klaus Conrad (1905–1961). Conrad used a methodology explicitly borrowed from Gestalt psychology to develop a new psychopathological and course-oriented perspective on schizophrenic psychosis, which has provided numerous insights to the field. His core idea was to position the gestalt-analytic method as a “third way” between the classic approaches of description (too static and not differentiated enough) and hermeneutics or interpretation (too unverifiable and speculative), both of which remained important but insufficient (Conrad 1958). This foundational argument is partially reflected in contemporary phenomenological psychopathology (Parnas 2011).

The work of Heidelberg psychopathologist Werner Janzarik, developed over decades, is also grounded in Gestalt and structural psychology. For Janzarik, normal and pathologically distorted psychological processes are structured on two levels: the structural and the dynamic. “Dynamic” refers mainly to affectivity and drive, while “structure” denotes enduring characteristics of the person, such as values, personality traits, and interaction patterns (Janzarik 1988). This theoretical framework has been fruitfully applied to various psychopathological areas, including psychotic syndromes (schizophrenic and affective), personality disorders, and, independently of diagnosis, the assessment of criminal responsibility in forensic evaluations. However, the highly differentiated and still not fully explored approach of “structural dynamics” is difficult to grasp, partly due to its language, and it contrasts with the prevailing trend toward simple and operational psychiatric terminology.

“Antipsychiatry”
Characteristic examples of psychiatry and psychotherapy’s particular exposure to fundamental issues, such as the concepts of illness and diagnosis, include the rise and significant influence of fundamentally “antipsychiatric” positions. Similar debates are much rarer in other medical disciplines. The fundamental critics of the 1960s and 1970s, who had quite diverse theoretical arguments, aimed to “expose” the supposedly scientifically grounded disease concepts of academic psychiatry as tools of exclusion used by bourgeois society against individuals who, although different or “noticeable” in their behavior, were not seen as ill or in need of treatment by these critics (Szasz 1972). Szasz himself, however, strictly rejected being labeled as an “antipsychiatrist.” His harsh critique was not directed at the field of psychiatry itself but at its uncritical medicalization and the use of compulsory psychiatric measures. From his perspective, psychiatry had unnecessarily and preemptively accepted becoming an instrument of social control, thus acting as a kind of “health police.”

Antipsychiatry should not be dismissed today as mere provocation or a quirky minority opinion. Many of its criticisms were entirely justified, especially regarding the psychiatric care situation in large hospitals at the time. Even from a contemporary standpoint, the questions raised by antipsychiatry remain relevant, even if one does not endorse the radical solutions proposed by figures like Thomas Szasz (1920–2012).

Neurobiological Research Approach
Since the late 1950s, the neurobiological research approach has experienced a strong and ongoing rise, initially driven by the discovery of the psychotropic effects of various substances. This research focused on scientifically assessing the therapeutic efficacy of neuroleptic, antidepressant, anxiolytic, and mood-stabilizing substances. Additionally, knowledge about the assumed or confirmed pharmacological mechanisms led to hypotheses about the etiology, particularly the pathogenesis, of mental disorders. In practice, this approach, seen in the dopamine hypothesis of schizophrenia or the norepinephrine hypothesis of depression, resulted in the use of “diagnostics ex juvantibus,” common in other areas of medicine. Here, conclusions about the biological nature of a mental disorder are drawn from the patient’s response or non-response to a specific psychotropic drug (Helmchen 1990).

Beyond evaluating the effects of psychotropic drugs, the influence of neurobiology increased further with the development of new diagnostic techniques. Examples include imaging methods, as well as neurophysiological, neurochemical, and molecular genetic research approaches. Historically, an interesting point is the repeated call to move away from the traditional nosology, which often reflects Kraepelin’s dichotomy of endogenous psychoses, and instead focus on syndrome-, symptom-, or function-oriented research. This strategy, known as the “denosologization” of psychiatric research, aims for a “functional psychopathology” that seeks to identify neurobiological correlates of specific mental functions, whether disturbed or undisturbed, such as affect regulation, cognitive processes, and memory (Benkert 1990; van Praag et al. 1987). This approach is linked with an increasingly critical assessment of Kraepelin’s dichotomy from a neuroscientific perspective (Möller 2008). The most recent development of this perspective can be seen in the Research Domain Criteria (RDoC) developed by the National Institute of Mental Health (NIMH) (Insel et al. 2010; Insel and Cuthbert 2015; see also the chapter on descriptive-psychopathological assessment in psychiatry).

New Therapeutic Approaches
In addition to classical psychotherapy methods, which strongly resemble their historical roots—primarily Freud-oriented psychoanalysis and behavior therapy based on behaviorism principles—there is a growing trend toward developing integrative models in both therapy and research. These models incorporate aspects of different therapeutic approaches depending on the type and severity of the disorder. For example, a combined treatment of anxiety disorders involving medication, behavior modification, and support from the social environment has proven superior. Additionally, the field of scientifically based psychotherapy has greatly expanded, partly due to the development of disorder-specific interventions. Examples include client-centered therapy, cognitive behavioral therapy (CBT), Gestalt therapy, mindfulness-based therapy, occupational therapy, and music and dance therapy.

Social Psychiatry
Another significant field of psychiatric research in recent decades is social psychiatry, which focuses on the complex interactions between the immediate (family and work) and broader (societal) environments of a mentally ill person. This includes the genesis, symptom manifestation, therapeutic response, and especially the long-term course of mental disorders, with a particular focus on rehabilitation aspects (Rössler 2004). Some key social psychiatric goals, set decades ago by the German Psychiatric Enquiry (Deutscher Bundestag 1975), such as community-based psychiatry following the “outpatient before inpatient” principle, have been at least partially achieved through regionalization and the establishment of integrative care models.

Operationalization
In recent years, there has been a strong trend toward codification and operationalization in psychopathology and psychiatric diagnostics. However, more complex frameworks, like Janzarik’s structural dynamic approach or recent developments in phenomenological psychopathology (Parnas et al. 2008), provide a counterbalance, though primarily in the theoretical-conceptual rather than practical-clinical domain.

The scientific-theoretical and historical background of the operationalized diagnostic systems, ICD-10 and DSM-5, is rooted in “analytical philosophy” (note: the term “analytical” here has no connection to “psychoanalytical”), which continues the neopositivist traditions of logical empiricism. This approach gained popularity primarily in the Anglo-American world and, later, in German-speaking regions. As an “analytical philosophy of mind” (Bieri 1981), this field provides the diverse intellectual framework for what is often referred to as Cognitive Science.

Different Psychiatric “Languages”
While the “linguistic turn” in philosophy, often associated with Ludwig Wittgenstein, did not significantly impact psychiatry for a long time, there was a renewed focus on fundamental methodological issues in psychopathological assessment and diagnosis starting around the 1960s. International studies on the comparability of psychiatric diagnoses were quite disillusioning, revealing the full extent of the incompatibility of different psychiatric “languages” (Wing 1971). This resulting dissatisfaction merged with the practical need for measurement tools that met statistical standards like validity and reliability, especially for evaluating newly developed psychotropic drugs. The “common endpoint” of these intertwined developments is today’s internationally widespread operationalized psychiatric diagnostics. Following the core concepts of “analytical philosophy of mind,” the psychiatric “language” is rigorously critiqued to expose ambiguities and contradictions. Clear definitions of symptoms, criteria catalogs, and linking rules, in short, operationalized decision-making processes (algorithms), are used to create reliable diagnostics.

Advantages and Disadvantages of Operationalization
Clear advantages of such operationalization include increased reliability, applicability across different etiopathogenetic hypotheses, easy computer-based analysis, and, not least, its function as a comprehensible terminological framework for training and education. However, the potential issues of an operational, criteria-driven approach must also be kept in mind. These include the tendency to “reify” originally descriptive entities due to practical use, the implicit discrediting of non-operational approaches, or the risk of reducing complex psychopathological situations, which might only emerge through repeated exploration or lie entirely outside it, to the “closest matching” operational criteria. If these complexities are hard to capture with criteria, they might be seen as scientifically insignificant. This could unduly narrow and oversimplify psychopathology (Hoff 2015; Saß 1990; Schwartz and Wiggins 1986).

Current Developments in the 21st Century
At the beginning of the 21st century, several important yet controversial debates have arisen in practice and research, continuing the history of psychiatry and developments post-1970. Key examples are outlined below.

No Unidimensional Explanatory Models
Fears that theoretical issues in psychiatry might be increasingly sidelined by the rapid growth of empirical data from the neurosciences have fortunately not been realized. On the contrary, there has been a growing willingness in recent years to continuously rethink the theoretical framework of clinical and scientific psychiatry in light of recent research findings. There is now broad consensus that unidimensional explanatory models for mental disorders are inadequate. However, the validity of the biopsychosocial model, essentially the greatest common denominator of different psychiatric approaches, is also being critically discussed. The key question is how to prevent this seemingly convincing model from becoming a superficial compromise that is not taken seriously in research, fails to generate creative impulses, and, in the worst case—contrary to its own core intention—revives dogmatic individual positions (Ghaemi 2010).

Neurophilosophy
A prominent example of the renewed interest in theoretical questions is the term “neurophilosophy.” Over the last few decades, a remarkable alliance has formed between empirical neuroscience and “analytical philosophy of mind,” known as neurophilosophy. Analytical philosophy of mind emerged earlier in the 20th century from dissatisfaction with classical dualistic theories of the mind-body problem. It argued that, before establishing facts or truths, one should first examine the language used to make these statements. In other words, the focus should be on the statements about a phenomenon before the phenomenon itself. This basic idea is usually referred to in the history of philosophy as the “linguistic turn.”

Things become even more concrete (and controversial) when fundamental concepts like free will, personal autonomy, and human responsibility are neurophilosophically questioned, and sometimes even denied, in light of current brain research. The much-discussed “neuroscientific manifesto” by Elger et al. (2004) is a notable example. The sometimes sharp debate about the need for a new, neuroscience-based image of humanity (Janich 2009; Roth 2003) shows how quickly these discussions extend beyond strict psychiatric and neuroscientific frameworks to address fundamental societal issues, similar to many “classic” authors like Kraepelin, Bleuler, and Freud. The new concept of the Research Domain Criteria (RDoC) will also need to address this topic consistently.

Empowerment of the Patient Role and Responsibility
Driven, though not invented, by the antipsychiatric criticism of the 1960s and 1970s, the roles of patients and caregivers in psychiatry have increasingly become the subject of nuanced discussions. Similar to other medical disciplines, the idea of empowerment has been gaining importance in psychiatry, emphasizing the enhancement of the patient role, especially patient responsibility, through the active involvement of individuals in therapy planning and execution. This includes a critical reassessment of the relationship between psychiatry and coercion, as well as moving away from the often unreflective paternalism of earlier times. An interesting but not yet sufficiently explored aspect of the tension between paternalism and patient autonomy is the realization that merely “handing over” ultimate responsibility to the patient in a simplistic form of shared clinical decision-making is not sufficient. The specific situation of the mentally ill person must be considered, as their cognitive, emotional, and evaluative abilities are often limited by the illness, even if rarely entirely absent. Ethical principles must be highly differentiated and specific to psychiatry. Achieving this goal requires not only formal (legal) or social scientific means but also the systematic integration of psychopathological knowledge .

The Role of Psychopathology
This leads to the question of what role psychopathology will play in the future development of psychiatry. Despite many rather pessimistic views that fundamentally question the scientific significance of psychopathology, there is also renewed attention to an expanded understanding of psychopathology. Ideally, this could revive its earlier claim to be the foundational science of psychiatry. However, a strengthened psychopathology would need to offer not only operational descriptions of phenomena for diagnostic and research purposes but also an “open” description that captures case-specific psychopathological issues beyond the criteria catalogs. A critical awareness of methods would need to be an integral part. This implies that the necessarily complex and interdisciplinary methodological environment of psychopathology must always be viewed with an understanding of the limitations of the scientific methods being employed. Finally, psychopathology must be consistently integrated into the history of psychiatric ideas, keeping the fundamental questions of the field open as long as current knowledge requires. These include the mind-brain problem, the subject-object question, and the status of personhood, including personal responsibility (often misleadingly called the “problem of free will”). Such openness is not a sign of indecisive hesitation but rather of respect for a central question that remains unresolved.

These considerations about the theoretical “place” of psychopathology are relevant to practice. Psychiatry must be aware not only of its particular social responsibility, especially in the current situation, but also of the tension among neuroscientific, psychopathological, social scientific, and neurophilosophical perspectives. It must actively engage and shape this dynamic field. In this crucial process for the future of psychiatry, psychopathology could (once again) take on the role of a critical guide. However, this is a high standard that has yet to be fully achieved (Andreasen 2007; Jäger 2016; Scharfetter 2010; Stanghellini and Broome 2014).

History of Psychiatry. Summary

The prehistoric and ancient cultures held a collective belief that the unknown could be explained by supernatural forces.

Despite limited archaeological evidence, our knowledge of prehistoric times remains fragmented. Nonetheless, it is reasonable to assume that primitive humans embraced magic and mythological explanations to explain phenomena they couldn’t understand. They world was populated by animistic spirits, both good and evil, inhabiting individuals and creating fears of demonic possession as punishment for defying gods.

Ancient civilizations like India, Babylonia, and China provided unique perspectives on mental health.The Babylonian civilization played a pivotal role in shaping early philosophical thought and mystical beliefs in the Mediterranean region.

Thales and Pythagoras, through their innovative perspectives and contributions, laid the groundwork for a more scientific understanding of mental processes. They shifted the focus from supernatural explanations to concrete, natural explanations rooted in observable phenomena.

These visionary thinkers challenged the status quo and initiated a paradigm shift that would eventually lead to the development of modern psychology and psychiatry. Their enduring influence underscores the enduring importance of their contributions to our understanding of the human mind.

In Ancient Greece Plato and Aristotle made foundational contributions to the understanding of the mind and its disorders. Plato focused on the interplay of rational and emotional forces and the potential for therapeutic intervention through education and rational discussion. Aristotle expanded this understanding by emphasizing empirical observation, cognitive processes, and the tangible aspects of human experience, laying the groundwork for future scientific and psychological attitudes

The Middle Ages was a complex era dominated by fear and superstition. Theological dogma often overshadowed reason and humanity. This resulted in tragic consequences, including persecution of the mentally ill and witch hunts. These events remind us of the dangers of ignorance and superstition. The eventual shift towards humanism paved the way for compassion and scientific progress. It emphasized the enduring importance of reason and empathy in society.
As a final example, the field of the history of psychiatry itself should be mentioned. The process of increasing professionalization in this area is evident not only in specific research projects within the narrow confines of individual psychiatric institutions but also in sustained efforts toward international and interdisciplinary collaboration.

The self-conception of psychiatry remains as heterogeneous in theory and practice, in research and clinical settings, as the many competing psychiatric research and treatment concepts. However, it is hard to claim that modern psychiatry has a stable self-confidence. Whether one speaks of postmodern theoretical diversity—or less kindly, of postmodern arbitrariness—or diagnoses an actual identity crisis within the field is ultimately irrelevant. What matters is that fundamental questions—what psychiatry is, what mental health and illness are, what diagnosis and therapy entail—cannot be ignored and must be addressed by utilizing existing knowledge and future findings from the field’s intellectual history, regardless of individual scientific or theoretical stances.

A scientifically grounded history of psychiatry, as outlined here, can demonstrate how every psychiatric concept—whether its self-understanding is scientifically-naturalistic, descriptive, hermeneutic, anthropological, or social-scientific—inevitably connects to specific theoretical assumptions, especially regarding the concept of humanity. This focus on the intellectual history from a pragmatic perspective is what gives historical research in psychiatry its true value for contemporary psychiatry. By effectively exploring its two main areas, institutional history and intellectual history, historical research in psychiatry can continue to be seen as a relevant and practical field of study, justified by its research focus.