Early improvement as a predictor of final remission in patients with treatment-resistant depression receiving electroconvulsive therapy with ketofol anesthesia

•The association between early improvement and eventual remission of ECT with ketofol anesthesia in TRD is unclear.•Early improvement after 3 ECT sessions is a predictor for final remission.•The lack of early improvement during a course of ECT may contribute to guiding decision-making in clinical practice.