General characteristics of the recruited subjects.

MDD: major depressive disorder; HC: healthy controls; M: male; F: female; HDRS: Hamilton Depression Rating Scale; GAF: Global Assessment of Function Scale. * HDRS were to rate the severity of depression in MDD patients, the higher the score, the more severe the depression. ** GAF assigns a clinical judgment in numerical fashion to the MDD patients’ overall functioning level. The scale ranges from 0 (inadequate information) to 100 (superior functioning).