Research library / Clinical trial
A randomized trial of an N-methyl-D-aspartate antagonist in treatment-resistant major depression
Zarate CA, Singh JB, Carlson PJ, et al. Archives of General Psychiatry 2006;63(8):856-64
This small study at the US National Institute of Mental Health tested whether ketamine, an anaesthetic that blocks NMDA receptors, could lift depression quickly. Eighteen people whose depression had not responded to other treatments each received one intravenous infusion of ketamine and one of placebo, a week apart, in random order. Depression improved within about two hours of ketamine, and the difference from placebo was very large the next day. Seven in ten responded within a day, but only about a third were still responding a week later. It was very small, the benefit was short-lived for most people, and ketamine's obvious effects make it hard to keep patients unaware of which infusion they received.
What it found
- Ketamine beat placebo within 110 minutes, and the difference stayed significant for a week
- Effect size was very large at 24 hours (d = 1.46) and moderate to large at 1 week (d = 0.68)
- The day after ketamine, 71% responded and 29% met remission criteria; 35% kept their response for at least a week