Depression has a high incidence and seriously affects people’s physical and mental health, but it is not an incurable disease. It is a mental illness with a good prognosis, and with effective treatment, the symptoms can be completely relieved and the patient can work, study and live normally. However, depression is an important feature that is prone to relapse. Some studies have reported that 30% of depressed patients cured by treatment relapse within one year; 50% of patients who have had one depressive episode will relapse, 70% of patients who have had two depressive episodes will relapse in the future, and almost 100% of patients who have had three depressive episodes will relapse. The main factors causing relapse are; inadequate dose and duration of antidepressant maintenance therapy, increase in stressful life events (e.g., interpersonal tension and loss), poor social adjustment, concomitant chronic physical illness, and inadequate social and family support. The most dangerous of the adverse prognoses of depression is suicide, and studies have shown that the suicide rate in depressed patients is 20 times higher than in the general population, and that about 15% of depressed patients succeed in committing suicide. The adverse outcome is often related to the lack of awareness of the disease, insufficient attention to the disease or taboo disease is not treated in a timely manner. Since suicide occurs only when the disease has reached a certain level of severity. Therefore, early detection of the disease and early treatment are very important for depressed patients.