Naturalistic follow-up in bipolar patients after successful electroconvulsive therapy

Background: Electroconvulsive therapy (ECT) is an effective treatment for acute depression, mania and mixed states. We evaluated the long-term outcome of patients with bipolar depression or mixed state, responsive to ECT. Methods: this observational follow-up study was conducted in 70 patients with Bipolar Disorder: 36 patients met DSM-IV-TR criteria for a major depressive episode (MDE) and 34 for a mixed episode (MXE). During the follow-up after ECT, the relapse rates and the duration of response and remission periods were recorded. Results: the mean duration of the follow-up was 57 weeks. 93% of the patients maintained at least a partial therapeutic response for more than 90% of the follow-up period. 73% of patients fulfilled the criteria for a full remission, 33% showed a depressive relapse and 10% a mixed relapse. No manic relapses occurred but almost 1/3 of the sample presented hypomanic episodes. MDE patients presented higher rates of remission compared to MXE ones. Patients with anxiety disorders reported earlier relapses than those without this comorbidity. Relapsed-patients showed higher functional impairment at baseline evaluation, compared to non-relapsed ones. Limitations: nonrandom allocation, limited sample size, possible influence of psychopharmacological treatment. Conclusions: Given several methodological limitations, this study cannot draw definite conclusions but could suggest that in treatment-resistant bipolar patients with severe depression or mixed state, ECT may represent a useful treatment option. Patients with mixed features, comorbid anxiety disorders and higher functional impairment present less favorable outcome. Future research on long-term efficacy of ECT and on clinical predictors of relapse is needed.