The Chinese Classification and Diagnostic Criteria of Mental Disorders (CCMD-3) diagnostic criteria for depressive disorders are as follows: Depressed mood is predominant, disproportionate to its situation, and can range from sullenness to grief, or even malaise. In severe cases, psychotic symptoms such as hallucinations and delusions may occur. Anxiety and motor agitation are significant in some cases. Symptom criteria: (1) loss of interest, unpleasant feelings; (2) loss of energy or fatigue; (3) psychomotor retardation or agitation; (4) low self-esteem, self-blame, or feelings of guilt; (5) difficulty in association or reduced ability to think; (6) recurrent thoughts of death or suicidal or self-injurious behavior; (7) sleep disorders, such as insomnia, early awakening, or excessive sleep; (8) sleep disorders. (7) Sleep disorders such as insomnia, early awakening, or excessive sleep; (8) Decreased appetite or significant weight loss; (9) Decreased sexual desire. Severe criteria Impairment of social function, causing distress or adverse consequences to the person. Duration of illness Criteria The symptom criteria and severity criteria have been met for at least 2 weeks. Exclusion criteria Exclude organic mental disorders, or depression due to psychoactive and non-addictive substances. International Classification of Diseases, 10th Revision (ICD-10 Classification of Mental and Behavioral Disorders. WHO, 1992). Depressive disorders classification and diagnostic criteria Three different forms of depressive episodes (mild, moderate, and severe). There is usually depressed mood, loss of interest and pleasantness, and decreased energy leading to increased exertion and decreased activity. It is also very common to feel a significant amount of lethargy after doing something. Other common symptoms are: (1) decreased ability to focus and pay attention; (2) decreased self-esteem and self-confidence; (3) feelings of guilt and worthlessness (even in mild episodes); (4) perceptions of a bleak and pessimistic future; (5) self-injurious or suicidal thoughts or behaviors; (6) sleep disturbances; and (7) decreased appetite. Mild depressive episode: Usually the symptoms are so distressing that there is some difficulty in continuing daily work and social activities, but the patient’s social functioning probably does not fail. Moderate depressive episode: Usually, moderately depressed patients have considerable difficulty continuing work, social or household activities. Major depressive episode: Patients with major depressive episodes often exhibit significant distress or agitation.