Continuation ECT: relapse prevention in affective disorders.

Relapse rates after the acute treatment of affective disorders with drugs or electroconvulsive therapy (ECT) are high (often 50-95%), despite preventive pharmacotherapy. In practice, some patients receive continuation and maintenance ECT after successful treatment of the index episode with ECT. We reviewed the charts of patients with affective illnesses who received continuation ECT (C-ECT) in our inpatient service from 1985 to 1991. In 33 courses of C-ECT, mean intertreatment interval was 10.1 days and the average duration of treatment was 10 weeks. One-year follow-up was available for 21 patients. Seven (33%) patients relapsed and needed re-admission within 1 year. The relapse rate for the patients with delusional depression was 42%, lower than the 95% reported for patients with delusional depression maintained on continuation pharmacotherapy before the C-ECT program started in our facility. No single factor examined was a significant predictor of relapse except C-ECT, which exhibited a sustained prophylactic effect for the year after the index episode.