Depression can be caused by biological, psychosocial, or genetic causes. However, it is difficult to make a clear distinction between all three factors. It is thought that these three factors play a role together as the cause of depression.

Depression can be caused by biological, psychosocial, or genetic causes. However, it is difficult to make a clear distinction between all three factors. It is thought that these three factors play a role together as the cause of depression.

  • Biological causes : Changes in serotonin and noradrenaline levels have been detected in patients with depression. These changes can be the cause of the disease or it can be the result. Serotonin and noradrenaline play a role in neurotransmitter transmission in the brain. In depression, problems occur in this transmission.

In depression, it is mentioned that serotonin does not fulfill its functions sufficiently. SSRI drugs are effective in eliminating this dysfunction.



Some neuropeptides (substance P, neuropeptide Y, CRH, galanin and vasopressin etc.), which are signal molecules released from nerve cells and act as a transmitter or modulator in excitable cells, may also play a role in the development of depression.

It is thought that some neurotrophins, which are involved in ensuring the structural integrity of nerve cells, their development and fulfillment of their functions, may also cause the emergence of depression.

  • Psychosocial causes: Different theories have been proposed regarding the psychosocial causes of depression.

Some explain depression as a decline or collapse in one’s self-worth. The loss of a loved one or object is manifested by introversion, rejection of the loss, the desire to punish oneself, the desire for forgiveness, sadistic, judgmental and destructive behaviors. The cruel superego wins the battle between the ego and the superego and kills the ego.

Some theories argue that the infant’s connection to the caregiver in the early years may be related to later depression. Babies whose desire for a stable and secure connection, comfort, support and curiosity is satisfied will feel valued, loved and supported in the future. If the connection is not strong, insecurity, worthlessness and depression will emerge in later life.

In some other theories, it is claimed that the person accepts the helplessness situations that he/she has experienced throughout his/her life, establishes inadequate social relationships, deteriorates self-confidence and results in depression.

  • Genetic causes : In recent studies, it has been revealed that genetic factors play a role in the emergence of depression. The incidence of the disease increases approximately three times in people whose first-degree relatives have been diagnosed with depression.

Those with a family history of depression may also have an early onset of the disease, more depressive episodes, and different psychological illnesses.

Genetic analyzes have shown some chromosomal abnormalities in patients with depression. These anomalies are more common especially in people who commit suicide due to depression.

Causes of depression:

There is often a triggering event for depression to occur. In the presence of low self-esteem, genetic predisposition, family history, etc., it becomes difficult for the person to cope with these triggers. These triggers reveal depression in people who cannot receive family support, friend support, etc.

  • Stressful events (separation, divorce, death of a loved one, etc.),
  • Birth,
  • Do not stay alone,
  • Alcohol addiction, substance use,
  • Head trauma,
  • Accident, disaster etc. painful events,
  • Diseases (hypothyroidism, cancer, diabetes mellitus, stroke, cerebrovascular diseases etc.),
  • Drugs used (beta blockers, calcium channel blockers, ACE inhibitors, cholesterol drugs, arrhythmia drugs, corticosteroids, oral contraceptives, epilepsy drugs, cancer drugs, allergy drugs, antibiotics, discontinuation of antidepressant drugs, etc.)