Electroconvulsive therapy reduces suicidality and all-cause mortality in refractory depression: A systematic review...

Depressive disorders are among the most common psychiatric disorders worldwide and associated with half of all suicides. There is robust evidence indicating that both electroconvulsive therapy (ECT) and repetitive transcranial magnetic stimulation (rTMS) effectively alleviate depressive symptoms in difficult-to-treat depression and enhance patient outcomes. However, there remains ongoing debate regarding their potential roles in preventing suicide and reducing all-cause mortality. Our study aims to investigate the impact of various neurostimulation techniques, including ECT, rTMS, and vagus nerve stimulation (VNS), on reducing suicidality, including suicidal ideation and completed suicides, as well as on overall mortality among individuals diagnosed with depression. In this systematic review and meta-analysis, we searched on MEDLINE via PubMed until January 9, 2024 for randomised controlled trials and controlled observational studies that investigated suicide and all-cause mortality outcomes after neurostimulation treatment for depression. Of the 1351 screened records we identified 26 studies eligible for inclusion in our systematic review. We included 11 studies on ECT (involving 17'890 subjects treated with ECT and 25'367 controls receiving treatment as usual), 5 studies on rTMS and 3 studies on VNS in our meta-analysis. In the cumulative cohort, 208 suicide deaths (1.70 %) were observed in the ECT group and 988 suicide deaths (5.02 %) were registered in the control group. Moreover, there were 511 deaths from all causes (3.13 %) in the ECT group, compared to 1325 deaths (6.64 %) in the control group. Thus, treatment with ECT demonstrated a significant 34 % decrease in the odds of suicide (OR 0.66, 95 % CI 0.50-0.88, p = 0.0047) and a 30 % reduction of death from all causes (OR 0.70, 95 % CI 0.62-0.79, p < 0.0001). The standardized mean difference (SMD) for suicidal ideation before and after ECT was -0.58 (95 % CI -0.10 to -1.07, p = 0.0177), suggesting a moderate effect size. We found no significant effect of rTMS on suicidal ideation with an SMD of -0.41 (95 % CI -1.01 - 0.19, p = 0.1795). In patients treated with VNS a 60 % reduction in the odds of death from all causes was observed (OR 0.40, 95 % CI 0.18-0.92, p = 0.0306). To conclude, there is consistent observational data supporting the protective effects of ECT against suicide and overall mortality. The systematic review protocol is registered online on PROSPERO, CRD42023412887.