Electroconvulsive therapy (ECT) is highly effective for depression, and ketamine at sub-anesthetic doses also produces rapid antidepressant effects. This systematic review and meta-analysis of 16 randomized controlled trials involving 928 patients examined whether adding ketamine to ECT improves outcomes. At the end of the ECT course, depressive symptoms were not significantly lower in the ketamine group compared to controls. However, depressive scores were lower after the first and after the third through sixth ECT sessions, particularly when ketamine was used as an add-on anesthetic. Ketamine did not improve overall response or remission rates and increased adverse events, especially cardiovascular and psychiatric side effects. Ketamine may accelerate antidepressant effects during ECT but should be used cautiously due to added risks.
For patients with major depressive disorder, adding a low dose of ketamine to electroconvulsive therapy (ECT) once a week improved remission rates and reduced psychiatric complications compared with giving ketamine before every ECT session. In a randomized trial of 134 patients, those receiving intermittent ketamine had a complication rate of 4.35%, far lower than the 20.93% rate in the repeated-ketamine group and similar to the 0% rate in the routine ECT group. Both ketamine regimens led to higher remission than ECT alone. Intermittent low-dose ketamine appears to boost ECT's effectiveness while minimizing side effects.
Adding a low dose of ketamine to electroconvulsive therapy (ECT) for major depressive disorder does not improve overall response, remission, or relapse rates, but it does speed up the treatment's effects. Patients receiving 0.3 mg/kg ketamine before ECT required fewer sessions to achieve a response (median 4 vs. 7 sessions) and remission (median 8 vs. 9 sessions), and also reduced suicidal ideation more quickly (median 3 vs. 6 sessions). The findings suggest ketamine can accelerate the onset of ECT's antidepressant benefits without affecting long-term relapse.