Typical clinical signs of depression include a decrease in three dimensions of activity: depressed mood, slowed thinking, and reduced volitional activity, with additional patients experiencing predominantly somatic symptoms. This can manifest itself specifically as significant and persistent depressive pessimism that is out of proportion to the reality of the situation. Patients with a milder degree of depression may feel sullen and unhappy, lacking interest in everything, feeling “depressed” and “unhappy”; those with a more severe degree of depression may feel pessimistic and desperate, with a sense that life is like a year and life is worse than death. Patients often say, “There is no point in living”, “I feel uncomfortable”, etc. Menopausal and elderly depressed patients can be accompanied by irritability, restlessness, dullness, flushing and sweating, while children and adolescents can show irritability (e.g., impatience, anger over the slightest thing). The typical depressive state of mind is also characterized by a morning-heavy and night-light rhythm, i.e., depressed mood is more severe in the morning and can be reduced in the evening. What are the dangers of depression? Patients in a depressed state suffer from mental and even physical pain, which affects the quality of life and the patient’s family or occupational function, and the risk of suicide in depression is high. It is best to receive timely, adequate and thorough treatment once depression is identified (i.e. acute treatment to obtain clinical recovery, with adequate consolidation and maintenance treatment), otherwise it will lead to chronicity and intractability of the disease.