A dose of 0.3 mg/kg of ketamine as an adjuvant anesthetic can accelerate the onset of the antidepressant effect of electroconvulsive therapy (ECT), according to a study published in The Journal of ECT.

In this double-blind, placebo-controlled study, patients with major depressive disorder (MDD; N=132) were randomized to receive either 0.3 mg/kg ketamine (n=66) or an isovolumetric dose of normal saline (n=66) before undergoing ECT with 1.5 mg/kg propofol for anesthesia. The primary outcome measures were the response and remission rates after ECT, defined as a reduction of ≥50% in the 24-item Hamilton Depression Rating (HAM-D) scale score and a sustained HAM-D scale score of <10, respectively. Patients who achieved remission were followed up in clinic every 2 weeks for 6 months.

There were no statistically significant differences in the response and remission rates between the treatment and control group (response rate: 80.95% vs 75%; remission rate: 74.60% vs 68.75%; P >.05). There were significant differences in the cumulative response and remission rates in time-to-event analysis; the median number of ECT sessions required to achieve a response was 4.0±0.41 in the treatment group and 7.0±0.79 in the control group. The median number of ECT sessions required to achieve remission was 8.0±0.29 in the treatment group and 9.0±0.48 in the control group.

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The study was limited by a potential compromise in statistical power because response and remission rates were not the primary outcomes in the initial trial. Nevertheless, the findings of this study may provide meaningful evidence in support of the use of 0.3 mg/kg ketamine in ECT.

The researchers found that the onset of the ECT effect was accelerated by a dose of 0.3 mg/kg of ketamine, but the antidepressant effect was not enhanced. “Some researchers do not support the use of adjunctive low-dose ketamine in routine ECT treatment,” the researchers wrote. “Nonetheless, because of the rapid antidepressant effect of ketamine, early improvements in depression could be expected with an adjunctive ketamine therapy in ECT, which may in turn be beneficial for shortening the hospital stay and hastening recovery from depression.”


Chen Q, Dong J, Luo J, et al. Effects of low-dose ketamine on the antidepressant efficacy and suicidal ideations in patients undergoing electroconvulsive therapy. J ECT. 2020;36(1):25-30.

This article originally appeared on Psychiatry Advisor