Superior anti-suicidal effects of electroconvulsive therapy in unipolar disorder and bipolar depression

Electroconvulsive therapy (ECT) has long been believed to reduce suicidal tendencies in patients with affective disorders; however, ECT recipients, who constitute the most severely ill and suicidal patients, are not eligible to participate in head-to-head randomized controlled trials. Large-scale studies are required to investigate the anti-suicidal effects of ECT vs psychopharmacotherapy.

A nationwide retrospective cohort study design was used. Data were obtained from the Taiwan National Health Insurance Research Database. Inpatients with unipolar disorder or bipolar disorder who received ECT (n = 487) were observed from 1 January 2000 to 31 December 2013 for suicide events. The non-ECT control cohort consisted of inpatients with psychopharmacotherapy randomly matched (ratio, 1:4) by age, sex, and diagnosis.

After potential confounds had been accounted for, the adjusted hazard ratio (HR) was 0.803, indicating that ECT recipients showed a 19.7% lower risk of suicide than control individuals. The stratum-specific adjusted HR was 0.79 in patients with unipolar disorder (P = .041) and 0.923 in patients with bipolar disorder (P = .254). Upon further stratification of the patients with bipolar disorder by their affective states, the adjusted HR was 0.805 (P = .046) for bipolar depression, 1.048 for bipolar mania (P = .538), and 0.976 for mixed bipolar state (P = .126).

Compared with psychopharmacotherapy, ECT exerted superior anti-suicidal effects in patients with unipolar disorder and bipolar depression; however, there was a lack of superior anti-suicidal effects of ECT in the treatment of patients with bipolar mania and mixed state.