BACKGROUND: This open, prospective study examined the effects of electroconvulsive therapy (ECT) in 10 adolescents with primary, endogenous, psychotic depression who were resistant to antidepressant pharmacotherapy. METHODS: Change in symptom severity from baseline was assessed weekly with Hamilton Depression Rating Scale (HDRS) ratings, and outcome was measured additionally at 1 month, and again at 1 year, post-ECT. RESULTS: All but 1 patient demonstrated dramatic improvement, with statistically significant decreases in mean HDRS score detected after the first week of treatment. All responders maintained the benefits of their treatment. CONCLUSIONS: The results provide evidence of the clinical effectiveness of ECT in adolescents with phenomenological characteristics shown to be predictive of ECT response in adults.