Electroconvulsive therapy and psychiatric readmission in major depressive disorder - A population-based register study.

Objective: The primary aim was to determine whether electroconvulsive therapy (ECT) is associated with reduced risk of psychiatric readmission in major depressive disorder (MDD).

Methods: This study was based on data from multiple Swedish population-based registries. All adult patients admitted to any Swedish hospital for moderate-to-severe MDD between 2012 and 2018 were included. Participants were divided into two groups depending on whether they received ECT during inpatient care. Follow-up was set at 30 and 90 days from discharge. Data were analyzed using logistic regression, and matching was conducted.

Results: A total of 27,851 unique patients contributed to 41,916 admissions. ECT was used in 26.8% of admissions. In the main multivariate analysis, the risk of both 30- and 90-day readmission was lower in the ECT group than in the non-ECT group. In a matched sensitivity model, the results pointed in the same direction for readmission risk within 30 days, but statistical significance was not reached. ECT-treated subgroups with superior outcomes on readmission risk compared with non-ECT treatment were older, unemployed, married, or widowed patients, those treated with antipsychotics or benzodiazepines before admission, with psychotic features, prior psychiatric hospitalizations, or family history of suicide. However, in patients below 35 years of age, ECT was associated with increased readmission risk.

Conclusion: This study suggests that ECT reduces the risk of psychiatric readmission in certain subgroups of patients with MDD. Since patients receiving ECT tend to be more difficult to treat, there is a risk of residual confounding.