Article

Effects of intravenous ketamine on explicit and implicit measures of suicidality in treatment-resistant depression.

Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, USA.
Biological psychiatry (Impact Factor: 8.93). 06/2009; 66(5):522-6. DOI: 10.1016/j.biopsych.2009.04.029
Source: PubMed

ABSTRACT Intravenous ketamine has shown rapid antidepressant effects in early trials, making it a potentially attractive candidate for depressed patients at imminent risk of suicide. The Implicit Association Test (IAT), a performance-based measure of association between concepts, may have utility in suicide assessment.
Twenty-six patients with treatment-resistant depression were assessed using the suicidality item of the Montgomery-Asberg Depression Rating Scale (MADRS-SI) 2 hours before and 24 hours following a single subanesthetic dose of intravenous ketamine. Ten patients also completed IATs assessing implicit suicidal associations at comparable time points. In a second study, nine patients received thrice-weekly ketamine infusions over a 12-day period.
Twenty-four hours after a single infusion, MADRS-SI scores were reduced on average by 2.08 points on a 0 to 6 scale (p < .001; d = 1.37), and 81% of patients received a rating of 0 or 1 postinfusion. Implicit suicidal associations were also reduced following ketamine (p = .003; d = 1.36), with reductions correlated across implicit and explicit measures. MADRS-SI reductions were sustained for 12 days by repeated-dose ketamine (p < .001; d = 2.42).
These preliminary findings support the premise that ketamine has rapid beneficial effects on suicidal cognition and warrants further study.

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