Depressive disorders - Mental disorders

The exact cause of depressive disorders is unknown, but genetic and environmental factors contribute to them.

Heredity accounts for almost half of all cases (less common in late-life depression). Thus, depression is more common among first-line relatives of depressed patients; concordance between identical twins is quite high. Apparently, genetic factors also influence the development of a depressive response in response to adverse events.

Other theories focus on changes in neurotransmitter levels, including mechanisms regulating choline, catecholamine (noradrenergic or dopaminergic), glutamatergic and serotoninergic (5-hydroxytryptamine) neutrotransmission (References to etiology Depressive disorders are characterized by quite pronounced and persistent sadness, resulting in impaired activity and decreased interest in life. The exact cause is unknown). Disorders of neuroendocrine regulation may play a major role, primarily due to possible disorders of 3 systems: hypothalamic-pituitary-adrenal, pituitary-pituitary-thyroid and hypothalamic-pituitary-somatotropin.

Psychosocial factors can also be involved. An episode of major depression is usually preceded by stress (especially a family divorce or the loss of a loved one); however, such events do not usually cause prolonged, severe depression in people who are not predisposed to affective disorders.

Individuals who have experienced an episode of major depression have a fairly high risk of relapse. People who are less resilient and/or have a tendency to be anxious are more likely to develop a depressive disorder. They tend not to take any active steps to cope with life's difficulties. The risk of developing a major depressive disorder is increased in the presence of other psychiatric disorders.

Women have a higher risk of developing depression, but no reasonable explanation for this fact has yet been found. Possible factors include the following: