AIMS: To synthesize the available experimental study evidence to estimate the effects of ketamine on suicide ideation (SI) in high-risk individuals.
METHODS: We conducted a systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Double-blind randomized controlled trials and open-label studies investigating the safety and effectiveness of ketamine on SI published up to October 2025 were identified. Data were pooled using random-effects meta-analysis. The main outcome was standardized mean difference on SI in high-risk individuals. Secondary outcomes were the percentage of adverse events and the moderator effects.
RESULTS: We identified 21 studies with a total of 927 participants meeting our inclusion criteria. The pooled effect size for the reduction of SI after ketamine treatment was significant and clinically meaningful (large effect size of -1.40, 95% confidence interval: -2.15 to -0.66, < 0.001, low-quality evidence). Dissociation (38.8%, = 0.014), nausea (31.6%, < 0.001), dizziness (24.7%, = 0.003), headache (22.0%, = 0.011) and anxiety (15.8%, < 0.001) were the frequently reported adverse events. Moderator analyses indicated that the effect was higher in younger individuals and those with severe SI. P P P P P P
CONCLUSIONS: Our findings highlight the effectiveness of ketamine in reducing SI in high-risk individuals, especially younger individuals and those with severe ideation. Nonetheless, additional research is required to better understand optimal dosing regimens and the potential long-term effects of ketamine treatment.
Psychedelic Science