Depressive disorder is a common mood disorder that can be caused by various reasons, with significant and persistent depression as the main clinical feature. Clinical manifestations can range from malaise to grief and even malaise; some cases have significant anxiety and motor agitation; severe cases can have psychotic symptoms such as hallucinations and delusions. Most cases have a tendency to have recurrent episodes, and most episodes can resolve with each episode; some may have residual symptoms or turn chronic. Depressive disorders mainly include: depression, dysphoria, psychogenic depression, depression in patients with brain or somatic disorders, depression associated with psychoactive or non-addictive substance-induced psychiatric disorders, and post-psychotic depression. Depression can occur in at least 10% of patients with manic episodes, at which point the diagnosis of bipolar disorder should be made. A survey in the United States in 1994 showed that the lifetime prevalence of depression was 17.1%, (12.7% for men and 21.3% for women) and 6% for bad mood (Kessler, 1998). A global collaborative study by the World Health Organization (WHO, 1993), focusing on 15 cities, investigated psychological disorders among general hospital attendees and found that 12.5% suffered from depression and dysphoria. In the WHO (1993) multicenter global collaborative study, the Shanghai survey showed that the prevalence of depression in general hospital outpatient clinics was 4.0%, and the prevalence of dysphoria was 0.6%.