The patient's pessimistic mood, sadness, melancholy, and loss of interest or fun in most daily activities are all manifestations of severe depression. Poor appetite and significant weight loss are also very obvious symptoms of severe depression. Secondly, depression is also manifested in insomnia or excessive sleep, and intractable sleep disorder has become an important feature of this disease, which has prompt value at an early stage. Insomnia can often appear before all other symptoms, and sleep returns to normal, which is often the first sign of this disease returning to normal. It is characterized by insomnia that has no reason, is stubborn, is difficult to heal for a long time, and lasts for a long time. It is characterized by early awakening, difficulty in falling asleep, shallow sleep, easy awakening, and inability to fall asleep after waking up in the middle of the night. In addition, significantly slow down or agitation; Feel worthless; The ability to think and concentrate is reduced, and forgetfulness.