Factors associated with the risk of relapse in schizophrenic patients after a response to electroconvulsive therapy: a retrospective study

Purpose: Electroconvulsive therapy (ECT) is an effective treatment for depression and schizophrenia. However, there is a high rate of relapse after an initial response to ECT, even with antidepressant or antipsychotic maintenance therapy. This study was carried out to examine the factors that influence the risk of relapse in schizophrenic patients after a response to ECT. Patients and methods: We retrospectively reviewed the records of 43 patients with schizophrenia who received and responded to an acute ECT course. We analyzed the associated clinical variables and relapse after response to the acute ECT. Relapse was defined as a Clinical Global Impressions Improvement score. 6 or a psychiatric rehospitalization. Results: All patients were treated with neuroleptic medication after the acute ECT course. The relapse-free rate of all 43 patients at 1 year was 57.3%, and the median relapse-free period was 21.5 months. Multivariate analysis showed that the number of ECT sessions was associated with a significant increase in the risk of relapse (hazard ratio: 1.159; P=0.033). Patients who were treated with adjunctive mood stabilizers as maintenance pharmacotherapy after the response to the acute ECT course were at a lower risk of relapse than were those treated without mood stabilizers (hazard ratio: 0.257; P=0.047). Conclusion: Our study on the recurrence of schizophrenia after a response to an acute ECT course suggests that the number of ECT sessions might be related to the risk of relapse and that adjunctive mood stabilizers might be effective in preventing relapse.