To clarify the epidemiology of adolescent suicide, a retrospective study was undertaken of suicides (1978 to 1982) and hospitalized suicide attempts (1979 to 1983) by adolescents aged 10 to 19 years in an affluent suburban area. Data included date of injury, demography (for both suicides and suicide attempts), and recorded personal and social history (available for attempts only). There were 11 deaths due to suicide (definite or possible) in the five years reviewed: seven male, 10 aged 15 to 19 years. The mean annual rate for suicide deaths (definite and possible, based on ICD codes) was 10.3 per 100,000 15 to 19 year olds, with male rates exceeding female rates. Male rates were lower in the study area than in Chicago, Illinois or the United States, but female rates were higher. Suicides represented an unusually high proportion of all adolescent deaths. Atypically, there were no firearm suicide deaths. Two hundred ten suicide attempts were studied: 77% aged 15 to 19 years, 70% female, and 82% white; 83% involved ingestion of medications or poisons. The mean annual suicide attempt rate was approximately 140 per 100,000 for 15 to 19 year olds, and 45 per 100,000 for 10 to 14 year olds, with female rates exceeding male rates. There was an association between suicide attempt dates and occurrence of holidays, and there was a peak in attempts at the end of the school year. Detailed analysis of personal and social attributes associated with suicide attempts was prevented by poor recording of relevant factors in the medical record.(ABSTRACT TRUNCATED AT 250 WORDS)