Inclusion Criteria:  a diagnosis of Major Depressive Disorder according to DSM IV or V and validated via Mini International Neuropsychiatric Interview (M.I.N.I.) right handedness capability of understanding and finishing self-rating scales capability of providing informed consent  Exclusion Criteria:  any other major psychiatric disorders following DSM-5 diagnostic criteria neurological diseases a history of drug abuse suicidal risk pregnancy any contraindication for brain MRI scan.