There is a correlation between depressive spectrum disorders, the number of depressive symptoms, the average number of relapses, and hereditary history. Relatives of depressed patients have been found to have various psychosomatic illnesses.

 Family history and heredity play a significant role in the predisposition to depression. At the end of the 20th century, a gene associated with bipolar disorder was identified on chromosome 11. However, it was subsequently discovered that defects in this gene are characteristic of other mental disorders. There is a hypothesis that the predisposition to depression is controlled by different genes located on chromosome IV and on the X chromosome.   

The hereditary factor plays an important role in the development of bipolar mental disorder. The development of this disease in persons with relatives with bipolar depression is fifteen times higher than in relatives of healthy people. People with a family member with bipolar psychosis are six times more likely to develop depression than those without a family member with the disorder.  

 Unipolar depression occurs in families with relatives with bipolar or unipolar depression.

 If a family member has had a major depressive episode, the risk of bipolar disorder or depression in other relatives doubles. In the presence of bipolar depression in the father and mother, this disease occurs in 75% of cases in children. In 25% – if one of the parents is sick. In patients with a genetic predisposition to depression, the function of glucocorticoid receptors in the brain neurons is insufficient . That is , there is a sensitivity of nerve cells to stress. Patient gender does not play a major role in the development of depression. And the prevalence of women among patients with depression is associated with social conditions.