Electroconvulsive therapy significantly reduces suicide risk in severe depression

The continued use of electroconvulsive therapy appeared warranted for reducing suicide risk among patients with severe depression, according to results of a registry-based cohort study published in JAMA Network Open.

“A recent large Danish register-based study showed that ECT is associated with an increased risk for suicide compared with non-ECT,” Ida Rönnqvist, MD, of the University Health Care Research Centre at Örebro University Hospital in Sweden, and colleagues wrote. “Other smaller studies reported that ECT is associated with both an increased and decreased suicide risk. These conflicting results, which could be explained by incomplete adjustment for potential confounding factors, mean that the effect of ECT on suicide risk is uncertain.”

To address this research gap, the researchers analyzed data from Swedish national registers of 28,557 patients (ECT group mean age, 55.9 years; non-ECT group, 45.2 years; 55.5% women) who received inpatient care between Jan. 1, 2012, and Oct. 31, 2018, for moderate depression, severe depression or severe depression with psychosis. They used propensity score matching in a 1:1 ratio to balance suicide risk factors at baseline between patients who did and did not receive ECT during the inpatient episode. By combining data from the Swedish National Quality Register for ECT and the Swedish National Inpatient Register, the researchers identified patients who had received ECT during the inpatient episode. Further, they identified suicide risk factors using national registers. Suicide within 3 and 12 months of inpatient care admission served as the main outcome, and Rönnqvist and colleagues adjusted for confounders using Cox regression analyses.

Among the matched sample of 5,525 patients in each group, the researchers reported death by suicide for 62 patients (1.1%) in the ECT group and 90 patients (1.6%) in the non-ECT group within 12 months (HR = 0.72; 95% CI, 0.52-0.99). Further, they noted a significant association between ECT and decreased risk for suicide among patients with psychotic features (HR = 0.2; 95% CI, 0.08-0.54) and those aged 45 to 64 years (HR = 0.54; 95% CI, 0.3-0.99) or 65 years or older (HR = 0.3; 95% CI, 0.15-0.59) but not among patients aged 44 years or younger (HR = 1.22; 95% CI, 0.68-2.16).

“This study supports the continued use of ECT to prevent suicide among inpatients with severe depression, especially older patients and patients with psychotic depression,” Rönnqvist and colleagues wrote. “This study was limited by potential residual confounding due to indication and management during the follow-up period.”

In a related editorial, Bradley N. Gaynes, MD, MPH, professor of psychiatry at the University of North Carolina at Chapel Hill’s School of Medicine, emphasized the importance of this research for informing the use of ECT for reducing suicide risk.

“This research provided the strongest evidence yet that the use of ECT, when applied to the proper group, is associated with a reduced risk for suicide,” Gaynes wrote. “This is important information that patients, families, health care professionals and payors can consider in deciding whether ECT is indicated for an individual with at least a moderate severity of MDD, with or without psychotic symptoms.”