Causes of depression are complex, but they can be conditionally divided into two types.
1 Biological reasons.
Genetic predisposition. Propensity to disease depressive disorders in relatives of the patient in two to three times higher than in people who do not have relatives with depression.
Furthermore, the appearance of depressive disorders involves many neurotransmitters (biologically active chemicals with which electrical pulse is transmitted is carried between nerve cells). The largest group of neurotransmitters are monoamines: norepinephrine, dopamine, epinephrine, serotonin, and acetylcholine. According to the theory of neurotransmitters, the disease can occur due to a reduction, or changes in the activity of these substances.
Found that certain parts of the brain in people suffering from depression have an excellent volume compared with the same areas of the brain healthy. It was also revealed an impressive difference in the metabolic activity of various parts of the brain in depressed patients and healthy people.
Change in metabolism in the disease observed in some endocrine glands. Since many patients with subclinical hypothyroidism noted the appearance of which has no effect on human physiology, but actively interacts with his emotional sphere.
2 Social reasons.
Stress factors in human social life play an important role in the occurrence of depression. Here, as the cause of the disease, in varying degrees, can be considered the loss of a loved one, stress at work, heavy relationships with loved ones, betrayal, financial incompetence, violation of social adaptation, etc.