Ketamine Anesthesia, Efficacy of Electroconvulsive Therapy, and Cognitive Functions in Treatment-Resistant Depression

Objectives Electroconvulsive therapy (ECT) is the most effective treatment for drug-resistant depression (DRD). Because a single infusion of ketamine may exert both a rapid antidepressant effect and a quick improvement of cognition, the aim of the present study was to assess whether ketamine, as an anesthetic drug for ECT, can augment the antidepressant activity of the procedure and/or exert a beneficial effect on cognition. Methods A total of 11 male and 34 female patients with DRD, aged 21 to 75 years, were included in the study. Fifteen patients (group 1) received only thiopental anesthesia, 15 patients (group 2) had their second and third ECT sessions with ketamine, and 15 patients (group 3) had ketamine for the second, fourth, sixth, eighth, and tenth sessions. Depression intensity was measured by the 17-item Hamilton Depression Rating Scale. Cognitive functions were measured before and after ECT, assessing visual-spatial abilities, verbal auditory memory, working memory, and executive functions. Results Before the ECT, the mean (SD) intensity of depression was 32 (6) points on the Hamilton Depression Rating Scale and the mean number of ECT sessions was 10.8 (1.5), with no difference between groups. After the last ECT session, the intensity of depression was significantly lower in group 3, compared with group 1. Cognitive assessments after ECT showed a more marked worsening in verbal memory in patients with added ketamine anesthesia. Conclusions The addition of ketamine may be connected with better antidepressant efficacy of ECT, compared with only thiopental anesthesia. However, patients with added ketamine had worse results on some of the indices measuring verbal memory.