Neuropsychological and mood effects of ketamine in electroconvulsive therapy: A randomised controlled trial

Background: Preliminary evidence suggests that the use of ketamine during electroconvulsive therapy (ECT) may be neuroprotective against cognitive impairment and have synergistic antidepressant effects. This study tested whether the addition of ketamine reduced cognitive impairment and enhanced efficacy over a course of ECT, in a randomised, placebo-controlled, double-blind study. Methods: Fifty-one depressed patients treated with ultrabrief pulse-width right unilateral ECT were randomised to receive either ketamine (0.5 mg/kg) or placebo (saline) in addition to thiopentone during anaesthesia for ECT. Neuropsychological outcomes (measured before ECT, after six treatments, and after the final ECT treatment) and mood outcomes (measured before ECT, and weekly after every three ECT treatments) were measured by a rater blinded to treatment condition. Results: Neuropsychological outcomes did not differ between groups. The ECT-ketamine group had a slightly greater improvement in depressive symptoms over the first week of treatment and at one-week follow up, though there was no overall difference in efficacy at the end of the ECT course. No psychomimetic effects were detected. Limitations: The study was conducted in a clinical setting, so not all aspects of ECT treatment were fully controlled. Thiopentone doses differed slightly between groups, in order to accommodate the addition of ketamine to the anaesthetic. Conclusions: The addition of ketamine did not decrease cognitive impairment in patients having ultrabrief pulse-width right unilateral ECT, but was safe and slightly improved efficacy in the first week of treatment and at one-week follow up. Clinical trials registration: Clinicaltrials.gov ID: NCT00680433. Ketamine as an anaesthetic agent in electroconvulsive therapy (ECT). www.clinicaltrials.gov