Depression is associated with the “person-environment” system, that is, with a social factor.

 The factors that trigger depression are:

· Increase in average life expectancy;       

· Urbanization:       

· Acute and chronic stress;       

· Population migration.       

 Most often, depression develops against the background of chronic stress, conflict situations in the family or work, and attempts to cope with it with the help of inadequate models of psychological defense. The most destructive for a person is a chronic stressful situation, or acute stress in youth. During this period, there is a need for an independent life, an orientation towards changing stereotypes, the need for a certain period of time to achieve the set goals. Increased parental guardianship leads to poor control skills. The tendency to blame young people for failures, remarks, insults form helplessness and increase the risk of developing depression. Repeated stress, constant setbacks, a distorted mental attitude, anticipation of unhappiness contribute to the development of stress. One problem that has not been overcome makes a person vulnerable to external circumstances and leads to a feeling of uselessness. If a person explains the reason for his failure by external circumstances beyond his control, then the risk of depression increases. Against the background of chronic stress, a person can get acute mental trauma and then a long period of depression occurs. Absence of parents, worries, divorce, wars, disasters contribute to depression. But sometimes the disease occurs without traumatic factors against the background of positive emotions and favorable events. 

Improper distorted upbringing, unfavorable family situation, fights, scandals, quarrels, mutual insults are the basis for the development of depression. Tough parenting measures, physical abuse, mental illness in parents, contributes to the development of depression in adolescents. With frequent family quarrels, children are drawn into the family situation. Then emotional vulnerability can accompany them throughout their lives. The early onset of depression at the age of 18-20 is associated with an unhappy childhood. A difficult childhood disrupts puberty, which affects the endocrine and nervous systems.  

Depression is also observed in menopause, especially if it flows against the background of a stressful situation.

Increased guardianship, protection of one person by another plays a bad role. Since if the protection disappears (death, divorce), then the second person is in a state of depression. Stress plays a large role in the first episode of depression, but in the case of bipolar depression, it may not trigger a relapse. With prolonged depression, it is impossible to determine whether the trigger is depression or stress. Following the theory of ignition sensitization, the first depressive episode occurs after prolonged stress, leaves behind neurobiological changes in the structures of the brain, in the limbic system, makes a person susceptible to the onset of a second episode, after mild stress or even without it.

The second depressive episode starts against the background of the same events or in the same setting as the first. In the case of bipolar depression, the episode may occur in a dual phase pattern .

 Psychotherapeutic treatment of depression is not possible if the social factors leading to it are identified.