Twenty-eight of 34 patients with major depression who completed a course of electroconvulsive therapy (ECT) and were classified as responders were administered lithium carbonate (Li) continuation therapy in the context of an open, prospective study. Twenty-four patients were followed for 6 months or until relapse; four patients dropped out of follow-up while still in remission. The probability of completing 6 months without relapse (by survival analysis, including the patients who dropped out as censored observations) was 65%. The eight patients who relapsed into depression all did so within 13 weeks. They were characterized by a shorter duration of their index depressive episode, a greater likelihood of having suffered an additional depressive episode in the preceding 12 months, and failure of an adequate trial of antidepressant medication before the ECT course. Novel pharmacological strategies may be needed in the post-ECT continuation therapy of patients who have a prior history of relapse and are demonstrably resistant to antidepressant medication.
