Objective: Acute electroconvulsive therapy (ECT) courses may end early because of rapid clinical improvement or interruption by an adverse event. However, the determinants of early termination and the subsequent clinical course remain poorly characterized. This study examined factors associated with the number of sessions in early-terminated ECT courses and their clinical outcomes.
Methods: We reviewed the records of adult psychiatric inpatients who received five or fewer bifrontal ECT sessions at a tertiary center between 2019 and 2023. After excluding non-clinical discharges, 523 patients were categorized into those receiving three or fewer sessions (n=136) and those receiving four to five sessions (n=387). Groups were compared on clinical, anesthetic, and outcome variables. Adjusted analyses and analyses stratified by diagnosis and American Society of Anesthesiologists (ASA) physical status examined the independence of the session-group effect, and missing clinical severity ratings were imputed.
Results: The groups did not differ in age, diagnosis, baseline illness severity, ASA physical status, or anesthetic parameters. Adverse-event-related termination occurred in 73.5% of patients receiving three or fewer sessions compared with 14.5% of those receiving four to five sessions, whereas rapid clinical response accounted for 85.0% of terminations in the latter group (p<0.001). After adjustment, receiving three or fewer sessions was associated with a sixteenfold increase in the odds of adverse-event-related termination (adjusted odds ratio: 16.18, 95% confidence interval [CI]: 9.70–26.97), independent of diagnosis and ASA status. Illness severity at ECT termination was greater in the ≤3-session group (d=1.43–1.76), but severity at hospital discharge did not differ between groups.
Conclusion: Among early-terminated ECT courses, session number primarily reflects whether treatment ended because of rapid clinical response or an adverse event, with adverse-event-related termination concentrated among the shortest courses, independent of diagnosis and medical risk. The absence of differences in clinical status at discharge suggests that, when appropriately managed, early termination due to adverse events is compatible with favorable short-term outcomes.