Abstract
Ketamine has attracted widespread attention as a potential rapid-acting antidepressant. There is also considerable interest in its use for the rapid treatment of patients deemed at risk for suicide. Here, we review the available evidence (open-label and randomized controlled trials) that examine the effects of ketamine on suicidal ideation (SI). Overall, data suggest that ketamine has a rapid albeit transient effect in reducing SI, though some studies had mixed results at different time points or using different assessments. Weaknesses to the existing literature include the small sample sizes of the studies, the exclusion of patients with significant SI at baseline from many of the studies, and the potential functional unblinding when participants are randomized to saline as placebo. The evidence supporting the clinical use of ketamine for SI is very preliminary. Although ketamine appears to a promising therapeutic option in a context where there is a great unmet need (i.e., patients at imminent risk of suicide), further controlled trials are needed to allow for meaningful clinical recommendations.