Multimodal Phenotyping in Adolescent Inpatient Depression: An Observational Study

Inclusion Criteria: * Between 10 and 20 years of age; * Diagnosis of major depressive disorder (MDD) or bipolar disorder (BD) according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Diagnosis is assessed using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) for participants aged ≥18 years, or the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL) for participants aged \<18 years; * Current moderate to severe depressive episode, defined as Hamilton Depression Rating Scale (HAMD) score ≥17; * Participants and 1 or 2 parents (patients' age\< 18 years old) provide informed consent after the detailed description of the study. Exclusion Criteria: * Prior treatment with repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS), electroconvulsive therapy (ECT), or standard psychological therapy within 6 months prior to screening; * Comorbidity with other DSM-IV Axis I disorders or personality disorders; * Judged clinically to be at serious risk of suicide; * Diabetes mellitus, hypertension, vascular and infectious diseases and other major medical comorbidities; * Unstable medical conditions, e.g., severe asthma; Neurological disorders, e.g., history of head injury with loss of consciousness for ≥ five minutes, cerebrovascular diseases, brain tumors and neurodegenerative diseases; * Mental retardation or autism spectrum disorder; * Contraindications to MRI (e.g., severe claustrophobia, pacemakers, metal implants); * Current drug or alcohol abuse or dependence; * Pregnant or lactating females.