Three groups of participants were recruited for the present study: (1) 30 healthy controls (16 males and 14 females, aged 22–38 years); (2) 32 patients with depressive disorder (15 males and 17 females, aged 25–40 years); and (3) 35 patients with anxiety disorder (16 males and 19 females, aged 26–43 years). The three groups were comparable in gender and age. Healthy controls were recruited from the university hospital staff, and were screened by psychiatrists and Hamilton anxiety and depression ratings scale to exclude any psychopathology. Patients were recruited from the Depression and Anxiety Disorders Clinic in Shenzhen Kangning Hospital, and the diagnoses were completed by psychiatrists in this hospital. The patients in Group 2 met the China Criteria of Mental Diseases III (CCMD-3) for anxiety disorders, but not for a depressive disorder, and were diagnosed with panic disorder (n = 9), social phobia (n = 13), or generalized anxiety (n = 13), and their scores of Hamilton Anxiety Scale were 24.25 ± 5.12 (mean ± SD). The patients in Group 3 met the criteria for CCMD-3 for major depressive disorder
