Investigators at four sites (Mayo Clinic, UMDNJ-New Jersey Medical School, Zucker Hillside Hospital, and University of Texas SW Medical Center, Dallas) randomize patients to receive either C-ECT or an aggressive pharmacological strategy (nortriptyline and lithium in combination, [NOR-Li]) for 6 months following response to acute phase ECT. Raters at each site evaluate symptoms and side effects. On the basis of edited videotapes obtained at regular intervals, a site-independent, blinded evaluator also assesses symptoms. A neuropsychological battery is administered prior to acute phase ECT, shortly after the ECT course, 3 months after the end of the acute phase treatment, and at the end of the 6-month continuation trial. These continuation therapies are compared in their effects on relapse, cognitive performance, global functioning, side effects, and perceived health status. NOR and Li levels are optimized by blood level monitoring. Bilateral ECT, at progressively increasing intervals, are used for C-ECT. Methods are included to ensure the integrity of clinical diagnoses, symptom severity assessment, data collection and entry, and treatment delivery. In all patients, surreptitious use of prescription or recreational drugs is monitored by urine testing.