We are recruiting physically healthy adolescents (ages 10-21 years old) who have a diagnosis of Major Depressive Disorder to participate in a research study seeking to better understand adolescent depression and suicide. This study involves a one-time visit to our clinic, providing blood and urine samples, and answering questions about mental illness. Participants will receive compensation up to $75. To determine eligibility, please call the Office of Psychiatric Research at 934-2484.