Patients Receiving 100 or More Electroconvulsive Therapy Treatments in a Nationwide Cohort.

INTRODUCTION: Very high cumulative exposure to electroconvulsive therapy (ECT) has primarily been described in individual case reports. We examined cumulative ECT exposure in a nationwide Japanese claims database to characterize patients receiving very high numbers of treatments. METHODS: We identified 3,733 patients who received ECT and classified them according to cumulative ECT exposure. Clinical characteristics of patients receiving 100 or more treatments were examined. RESULTS: Among 3,733 patients who received ECT, 39 (1.0%) received 100 or more treatments. These patients had treatment durations of several years and substantially greater numbers of psychiatric hospitalizations and cumulative hospitalization days. Clozapine use increased across cumulative ECT exposure categories, although it was recorded in only 13% of patients receiving 100 or more treatments. CONCLUSION: Patients receiving 100 or more ECT treatments represent an identifiable subgroup of ECT recipients characterized by prolonged and recurrent psychiatric care.