Rapid Antidepressant Effect of Ketamine in the Electroconvulsive Therapy Setting

OBJECTIVES: Studies now provide strong evidence that the N-methyl-D-aspartate receptor antagonist ketamine possesses rapidly acting antidepressant properties. This study aimed to determine if a low dose of ketamine could be used to expedite and augment the antidepressant effects of electroconvulsive therapy (ECT) treatments in patients experiencing a severe depressive episode. MATERIALS AND METHODS: Subjects with major depressive disorder or bipolar disorder referred for ECT treatment of a major depressive episode were randomized to receive thiopental alone or thiopental plus ketamine (0.5 mg/kg) for anesthesia before each ECT session. The Hamilton Depression Rating Scale (HDRS) was administered at baseline and at 24 to 72 hours after the first and sixth ECT sessions. RESULTS: Electroconvulsive therapy exerted a significant antidepressant effect in both groups (F2,24 = 14.35, P < 0.001). However, there was no significant group effect or group-by-time interaction on HDRS scores. In addition, post hoc analyses of the time effect on HDRS showed no significant HDRS reduction after the first ECT session for either group. CONCLUSIONS: The results of this pilot study suggest that ketamine, at a dose of 0.5 mg/kg, given just before ECT, did not enhance the antidepressant effect of ECT. Interestingly, the results further suggest that the coadministration of ketamine with a barbiturate anesthetic and ECT may attenuate the immediate antidepressant effects of the N-methyl-D-aspartate antagonist.