The symptoms include mood change, cognitive change, will and behavior change, physical symptoms, etc.: 1. Mood change: the patient has persistent depressed mood, almost most of the time every day, feeling sad, empty, pain and other negative emotions; 2. Patients feel that they are useless and believe that all the bad things in life happen because of themselves; 3, will and behavior changes: patients’ social functions are seriously impaired, lack of interest in daily activities, no way to carry out normal study, work and social life; may be accompanied by symptoms of depressive rigidity, that is, patients do not have any active request or action, extremely unresponsive, often sitting still or There may be pessimism and anhedonia, hallucinations and delusions, hypofunctionality, loss of confidence in life, accompanied by serious suicide attempts and actions; 4, physical symptoms: a large proportion of patients with major depression will have generalized pain, dizziness, tinnitus, insomnia and other physical symptoms, but the physiological examination is normal and there is no organic lesion.