The diagnostic criteria of depression are as follows: 1. duration of illness: at least 2 weeks, and the majority of time in 2 weeks every day with depression; 2. clinical symptoms: including depressed mood, no sense of pleasure, do not want to do things, reduced interest, fatigue, slow thinking, loss of appetite, insomnia and even the emergence of suicidal ideas or behavior, at least 5 of the 9 criteria can be diagnosed depression; 3. severity. Depression can be diagnosed if it seriously affects the patient’s life, work, interpersonal interactions and causes suffering. When diagnosing depression, there are usually three criteria: clinical symptoms, duration of illness and severity, all three of which are met at the same time to diagnose depression.