Introduction:
Electroconvulsive therapy (ECT) is a highly effective treatment for severe depression, including treatment-resistant depression (TRD). Modern ECT is performed under general anesthesia, raising the question of whether different anesthetic agents can influence the antidepressant efficacy of ECT. This systematic review examines how anesthetic choice affects therapeutic outcomes in patients with depression undergoing ECT.
Methods:
This review followed PRISMA 2020 guidelines. We searched Cochrane, PubMed, and EMBASE (2000–2025) for comparative studies of anesthetics in adult patients with TRD receiving ECT. Primary outcomes were depression severity improvement, response/remission rates, and number of ECT sessions to response. Of 547 records identified, 463 abstracts were screened. 45 full-text articles were assessed, and 31 studies met inclusion criteria for final analysis. Data were qualitatively synthesized due to heterogeneity.
Results:
Across 31 studies, anesthetic choice influenced the speed of antidepressant response, particularly within the first one to two treatment sessions. Ketamine used as an induction or adjunct anesthetic was repeatedly associated with significantly faster reductions in depressive symptom severity. Several trials reported greater early symptom improvement and higher early remission rates with ketamine-based anesthesia, suggesting that ketamine-based anesthesia may warrant consideration during ECT. By the end of an ECT course, depressive symptom scores generally converged across anesthetic groups. Evidence regarding whether ketamine reduced the total number of ECT sessions required was mixed.
Conclusion:
Anesthetic selection meaningfully influences the temporal efficiency of ECT for depression. Ketamine-based anesthesia is consistently associated with more rapid antidepressant response, particularly during early treatment sessions, while overall end-of-course efficacy appears comparable across anesthetic agents. Earlier symptom relief may be clinically important in patients with severe, treatment-resistant, or high-risk depression where rapid improvement is critical. These findings support reframing anesthetic choice as a modifiable component of ECT that can shape treatment dynamics rather than a neutral procedural factor.
