Inclusion Criteria:  1.patients who attend psychiatric outpatient clinics or who are admitted to the psychiatric inpatient ward at the above sites. 2.clinical diagnosis of depression-related disorders and scores of HDRS-17 ≥ 10. 3.psychotropics have been kept unchanged for at least a month. 4.aged 10 to 24. 5.serum 25-hydroxycholecalciferol (25-OH-D) levels lower than 20 ng/ml.  Exclusion Criteria:  1.endocrine disorders  including diabetes thyroid parathyroid disorder.  2.serious neurological disorders  epilepsy severe traumatic brain injury neurodegenerative conditions 3.liver disease 4.kidney disease 5.heart disease 6.other serious health conditions.  7.severe mental disorders  Organic mental disorders Alcohol or substance use disorders active within 3 months Schizophrenia Delusional disorder Psychotic disorders not elsewhere classified. Bipolar disorder. Autistic spectrum disorder. Anorexia nervosa. Mental retardation with IQ less than 70. High violence or suicide risk.  8.Patients use drugs or herbals interfering with vitamin D metabolisms  phenobarbital phenytoin anti-tuberculosis drugs thiazide diuretics. 9.Pregnant or expect to be pregnant during study participation.