The causes of depression are summarized as follows: 1. Genetic factors: Genetic factors have a definite role in the causes of depression, but this mainly refers to affective psychosis depression. However, depression is not a hereditary disease, and the study of heredity is mainly through the investigation of genealogy and the study of twins. 2, psychological and social factors: more than half of the first onset of depression patients can be found to have psychological and social factors, but there is a lot to tell, the onset of depressive neurosis and reactive depression are without exception the presence of psychological and social factors, especially the latter is obvious, there is no mental stimulation what to reactive depression? 3, biochemical factors: when a person suffers from depression, there is often a decrease in certain chemicals in the brain called neurotransmitters. It is believed that if there is an imbalance between the two neurotransmitters, 5-hydroxytryptamine and norepinephrine, it can lead to depression or anxiety. reduced 5-hydroxytryptamine and norepinephrine often lead to depressed mood, decreased motivation, and changes in appetite and libido. 4, neuroendocrine dysfunction: many studies have found that depressed patients have abnormal hypothalamic a pituitary an adrenal axis function, depressed patients have increased levels of plasma corticosteroids and 17-hydroxycorticosteroids. 5. Physical illness: Many physical illnesses and conditions, such as stroke, heart attack, cancer, chronic pain, diabetes, hormone disorders and advanced illness, can often lead to depression. If you or someone you know is suffering from a somatic disease and has symptoms of apathy or is unable to address their basic physical needs, you should contact your doctor. These symptoms may be an emotional response or subjective reaction to a somatic illness, or the person may have a comorbid depression that requires treatment. 6. Personality factors: People who are pessimistic, have low self-confidence, have poor thinking patterns, are overly worried or feel little control over life events are more likely to experience depression. 7, other factors: some drugs may cause depression (such as reserpine), in addition, often too much alcohol consumption can sometimes lead to depression.