Investigates potential predictors of suicidal behavior in adolescent psychiatric patients (N=60) during an 18-month follow-up period. Follow-up suicidality was most strongly predicted by high intake levels of hopelessness, and an increase in or persistent problems with depression. Proposes a model in which the impact of family functioning on adolescent suicidality is mediated by its impact on individual functioning. (Contains 53 references and 2 tables.) (Author/GCP)