SummaryThe authors examined reports addressing the question of whether electroconvulsive therapy (ECT) is more effective in psychotic or nonpsychotic depressive disorders. Most ECT studies did not consider the issue directly, and those that did had varying methodologies and results. The authors then analyzed the data of 33 depressed patients to clarify the differential response to ECT in 13 psychotic and 20 nonpsychotic patients. The subjects were also examined as to type of electrode placement. ECT produced a greater reduction in Hamilton Depression Rating Scale scores in the psychotic depressives as compared to the nonpsychotics after an average of 9.2 treatments. The two patients who were nonresponders to ECT were both nonpsychotic.