Relapse following electroconvulsive therapy

Irrespective of the treatment method used, there is a strong tendency to relapse into depression if treatment terminates. The purpose of this retrospective study is to investigate the relapse rate and the time elapsing before relapse after electroconvulsive treatment (ECT) and what was done to prevent this.

The ECT records and case notes of patients who received electroconvulsive therapy in the period 1960 - 1995 at three psychiatric departments at Dikemark Hospital were systematically reviewed. Relapse was defined as recorded, definite recurrence of depressive symptoms in patients who had achieved an improvement following a series of ECT treatments. The observation period is defined as the time since completing the first ECT series at Dikemark, up to and including 31 December 1995.

The median observation period following the patient's first ECT series at Dikemark was nine years (spread: 3 months - 44 years). Of 120 patients, 56 (47 %) who were described as show-ing an improvement after the first ECT series suffered a relapse in the course of the first six months. A total of 86 (72 %) suffered a relapse after an average of 13 months (median three months), but none of the seven who improved following their first-time depression suffered a relapse. After the first ECT series, 84 patients (70 %) received antidepressants and/or lithium to prevent relapse. An improvement was described after 87 of 100 repeated ECT series that were administered to 46 patients. In 58 (67 %) of these cases, relapse occurred within six months.

The relapse rate was high. The results indicate that follow-up treatment with antidepressants after electroconvulsive therapy should be supplemented with other measures to reduce the rate of relapse in cases of depression.