Background: Electroconvulsive therapy (ECT) is one of the most effective treatments for major depressive disorder (MDD), especially in cases of treatment-resistant MDD. Because of their pharmacological profiles, benzodiazepines (BZDs) are suspected to decrease the efficacy of ECT. This study investigated the effect of BZDs on ECT-induced clinical outcomes and ECT course parameters in patients with MDD.
Method: The impact of BZDs on severity of depression (Montgomery-Asberg Depression Rating Scale scores) and on ECT course parameters (seizure threshold, clinical and electroencephalographic seizure duration) was investigated in 70 patients with MDD who received an ECT course using dose-titration method (22 received concomitant BZDs).
Results: Lower remission rates (52.0%) and smaller decreases in Montgomery-Asberg Depression Rating Scale scores were observed in the non-BZD group than in the BZD group (81.2%, P = 0.02). There were no significant differences between the 2 groups regarding seizure duration and seizure threshold.
Limitations: This was a retrospective study. Impact of BZDs on anxiety and cognition was not assessed.
Conclusions: Benzodiazepines increased the clinical efficacy of ECT when delivered using dose-titration method and bitemporal stimulation. Further studied are needed to understand the interaction between BZDs and ECT on clinical outcomes.