A total population of high-school students aged 16-17 years in a Swedish town was screened for depression and previous suicide attempts, and 2300 students (93.3%) participated. Those with high depression scores (12.3%) and previous suicide attempts (2.4%), as well as controls matched for gender and education, were interviewed for diagnosis (DICA-R-A), and 88.8% participated. The 1-year prevalence of major depression was 5.8% and the lifetime prevalence was 11.4%, with four girls being represented for every boy. A depression lasting for at least 1 year was the most common type. Dysthymia was found in 2% (two girls for every boy). Short hypomanic episodes were present in 13.2% of those with a lifetime diagnosis of major depression.