Long-term clinical efficacy of maintenance electroconvulsive therapy in patients with treatment-resistant schizophrenia on clozapine

•Further improvement of psychotic symptoms with an acute course of electroconvulsive therapy (ECT) demonstrated that ECT could be an augmenting option in patients with treatment-resistant schizophrenia on clozapine.•The maintenance electroconvulsive therapy (M-ECT) was able to maintain the improved symptoms elicited by acute ECT, but without M-ECT, gradual deterioration of psychotic symptoms occurred.•Acute ECT and M-ECT did not cause remarkable sustained or serious adverse events, including persistent memory disturbance, except for mild agitation, headache, and nausea.