Causes of Depression

Dr. Gregor Kowal explaining patients causess of depressions — Dr. Gregor Kowal is a German-Board Certified Consultant in Psychiatry and Psychotherapy. He graduated from the University of Heidelberg, Germany. Dr. Kowal has held leadership and teaching positions, serving as Head of Department and later as Medical Director at renowned psychiatric hospitals across Germany. He specializes in the treatment of various psychiatric conditions, including depressive disorders

Causes of depression are complex and not entirely identified. They involve multiple sources, including highly heterogeneous genetic and biological factors as well as psychosocial and environmental influences. Thus, no single cause can explain the onset of depression. There is a scientific consensus that depression originates from an interaction of biological, genetic, psychological, and social factors.

The role of genetic and environmental factors varies from person to person. Most models explaining depression are based on genetic predisposition, neurobiological imbalances, and certain developmental and personality factors (psychosocial factors).

People affected by depression generally have a lower tolerance for emotional, physical, and life stressors than healthy individuals. This particular vulnerability also plays a significant role in triggering and sustaining depression.

Neurobiological Causes

The immense progress in the neurosciences, which started in the mid-20th century, showed that depressed people have in their brain an imbalance of the neurotransmitters. The neurotransmitters allow the nerve cells to communicate with each other. The neurotransmitters can be influenced by variety of factors, such as genetics, social circumstances, or physical illnesses. Treatment with anti-depressants helps to restore the balance of neurotransmitters and as its effect to remove the symptoms of depression.

Genetic Influences

A large body of evidence from family and twin studies points to genetic contributions for causing depression. The twin studies compare disease frequencies in identical twins. Only half of the identical twins gets ill if the sibling developed depression. It means that other factors than genetics contribute to the onset of depression in the second half. The family history puts their offspring at an increased risk of depression. As a result, a child with one depressed parent is 10-15% more likely to develop depression than the average. If both parents suffer of depression, the risk for their children increases to 20-40%. Such results prove the multi-factorial genesis of depression.

The exploration of numerous genes and their influence on depression didn’t show one particular gene causing the illness. This means that an interaction of several genes is necessary to trigger the onset of depression. So even the genetic component of depression requires synchronized action of various genes.

Psychosocial Causes of Depression

Many studies have confirmed that among the psychosocial factors, stressful severe life events, such as breakups, loss of a loved one, or job loss, are likely to contribute to the onset of depression.

Wang et al. (2016) highlight that socioeconomic status, and the severity of depression are negatively related. The scientists claim that a fourfold increased risk of depression is the attribute of sexually or physically abused women in childhood compared with women without such experiences.

Certain physical illnesses (e.g., thyroid disorders), medications (e.g., birth control pills, antibiotics), or substance abuse can trigger depression.

In addition, the attachment theory of Bowlby (1977) claims that disrupted affectional bonds between children and caregivers have been the key contributors to psychopathology, including depression and anxiety.

Similarly, the developmental pathway from early conduct problems to adult depression explains another possible cause of depression.

Environmental Effects Triggering Depression

The illustration is collage. The picture is held by two hands. The collage contains different objects, such as a mobile, fragments of a landscape, and animals. On the screen of the mobile, we see a man cutting a tree. with smoke over it. The collage is showing the destruction of the environment, causing distinct psychiatric disorders — *Devastated environment, stress and pollution* *facilitates the onset of depression*

Converging evidence indicates that environmental exposures can contribute to the onset of depression. Air pollution, use of herbicides, food preservatives and other chemicals in every area of urban life can affect the activity of certain brain cells (i.e. serotonergic and dopaminergic neurons.)

Cultural Background and Depression

The cultural factors may influence symptoms of depression. For instance, in some cultural contexts, mental distress is primarily expressed through physical symptoms. This can sometimes make it challenging for doctors and psychologists to identify depression. Therefore, while diagnosing depression it’s essential to consider culture-specific factors and its nuances.

Frequency, Ethnic and Gender Differences

This condition occurs in people of all cultures, all social classes, and nationalities
Race or an ethnic origin has no influence on the development of depression.
Currently, there are mathematically 340 million cases of depression existing worldwide.
While approximately 25% of adult women develop depression only about 10 % of all men affected.
20% of all Germans develop depression once in their life. Worldwide figures vary between 8-20%.
The average age of manifestation of a depressive disorder lies between the ages of 20 – 40.