Objective: To describe the early adult psychopathological and social outcomes of adolescents who deliberately poisoned themselves. Method: Prospective cohort study with a 6-year follow-up of 132 of 158 (84%) adolescents who, between ages 11 and 16 years, had taken part in a randomized trial of a brief family intervention after deliberate self-poisoning. Comparisons were made with a sample of participants matched for age, gender, and childhood social class. Both groups were assessed using standardized measures of psychopathology and social functioning. Results: In most cases (93/132 or 70%) self-harm stopped within 3 years. Psychiatric disorders, particularly depression (74/132 or 56%), were prevalent, and self-harm in adulthood was restricted to this subgroup. There was a strong association between childhood adversity, in particular childhood sexual abuse, and self-harming risk in adulthood. Adulthood adversity also added to the risk, especially for those who had experienced index episode major depression. These associations were not mediated by childhood problem solving and hopelessness. Conclusions: For some young people, deliberate self-poisoning in adolescence seems to be part of a complex and continuing network of problems, marked by high rates of psychopathology, comorbidity, with other disorders and high psychosocial adversity. (Contains 1 figure and 5 tables.)