Association Between Concomitant Anticonvulsants and Clinical and Cognitive Outcomes of Electroconvulsive Therapy for Depression

The impact of concomitant anticonvulsant medications on electroconvulsive therapy (ECT) outcomes is not firmly established, with previous studies yielding inconsistent results. This study examined associations between concomitant anticonvulsant use and clinical and cognitive outcomes of ECT for depression. A retrospective cohort study was conducted in 511 adult inpatients who initiated an acute ECT course for an ICD-10 unipolar or bipolar depressive episode between December 2016 and June 2024. Outcomes included Clinical Global Impression - Improvement (CGI-I) after final ECT, time to reorientation after each session, and electroencephalographic (EEG) and motor seizure duration after each session. Data were analysed using ordinal logistic regression, mixed-effects parametric survival models, and linear mixed-effects models. Of the 511 participants, 107 (20.9 %) were receiving anticonvulsants at pre-ECT baseline. Concomitant anticonvulsant use was associated with a significantly less favourable therapeutic outcome on the CGI-I (adjusted odds ratio = 1.60, 95 % CI: 1.05-2.44, p = 0.028). Conversely, patients on anticonvulsants reoriented significantly faster (adjusted hazard ratio = 1.42, 95 % CI: 1.12-1.80, p = 0.004), as did those whose nighttime dose of anticonvulsant was withheld before ECT (adjusted hazard ratio = 1.24, 95 % CI: 1.02-1.51, p = 0.028), compared to those not on anticonvulsants. Anticonvulsant use was not significantly associated with EEG or motor seizure duration in non-titration sessions. Concomitant use of anticonvulsants in patients treated with ECT for depression was associated with worse clinical response, despite a marginally faster recovery of orientation immediately after treatment sessions. Use of anticonvulsants during ECT requires careful clinical consideration.