IMPORTANCE Electroconvulsive therapy (ECT) is indicated for severe depression, including depression with psychosis, catatonia, and/or an elevated suicide risk. However, the association of ECT with suicide risk is uncertain.OBJECTIVE To determine the association between ECT and the risk of suicide in patients with unipolar major depressive disorder. DESIGN, SETTING, AND PARTICIPANTSThis registry-based cohort study used patient data from Swedish national registers. Patients with a record of inpatient care between January 1, 2012, and October 31, 2018, for moderate depression, severe depression, or severe depression with psychosis were included in the study. Propensity score matching (1:1) was used to balance risk factors for suicide at baseline between patients treated with and without ECT during the inpatient episode.EXPOSURES Data from the Swedish National Quality Register for ECT and the Swedish National Inpatient Register were combined to identify patients who had received ECT during the inpatient episode. National registers were used to identify risk factors for suicide. MAIN OUTCOMES AND MEASURESSuicide within 3 and 12 months of admission to inpatient care was analyzed. Cox regression analyses were used to adjust for confounders. RESULTSThe study included 28 557 patients (mean [SD] age, ECT group, 55.9 [18.4] years; non-ECT group, 45.2 [19.2] years; 15 856 women [55.5%]). In the matched sample of 5525 patients in each group, 62 patients (1.1%) in the ECT group and 90 patients (1.6%) in the non-ECT group died of suicide within 12 months (hazard ratio [HR], 0.72; 95% CI, 0.52-0.99). Electroconvulsive therapy was significantly associated with a decreased risk of suicide in patients with psychotic features (HR, 0.20; 95% CI, 0.08-0.54) and those aged 45 to 64 years (HR, 0.54; 95% CI, 0.30-0.99) or 65 years or older (HR, 0.30; 95% CI, 0.15-0.59), but not in patients aged 44 years or younger (HR, 1.22; 95% CI, 0.68-2.16). CONCLUSIONS AND RELEVANCEThe results of this cohort study support the continued use of ECT to reduce suicide risk in hospitalized patients who are severely depressed, especially those who are older than 45 years and those with a psychotic subtype.

Objectives: Electroconvulsive therapy (ECT) is used in some cases of postpartum depression (PPD) and postpartum psychosis (PPP). The risk of relapse for PPD and PPP after ECT is unknown. This study compared the relapse rate after ECT between women who had been treated for PPD and/or PPP and women who had been treated for depression and/or psychosis outside the postpartum period. Methods:The Swedish National Quality Register for ECT and the Swedish National Patient Register were used to identify women with PPD and/or PPP who had been treated with ECT within 6 months after delivery. For each case, a control (treated with ECT but not postpartum) patient was also selected. A Kaplan-Meier estimator was used to calculate the relapse rate (defined as rehospitalization or suicide) after ECT. Cox regression was used to identify variables associated with relapse.Results: A total of 180 patients were included in each group. The proportions of patients who suffered relapse after 6 months, 1 year, and 2 years were 28%, 31%, and 40% for the postpartum group and 39%, 50%, and 55% for the nonpostpartum group. Treatment with benzodiazepines, several previous psychiatric admissions, and the absence of improvement after ECT were associated with relapse. Conclusions:The risk of relapse after ECT is lower for patients with PPD and/or PPP than for patients outside the postpartum period, but the risk is nonetheless substantial in both groups.