The Effect of a Single Dose of Intravenous Ketamine on Suicidal Ideation: A Systematic Review and Individual Participant Data Meta-Analysis.
Level 1 - systematic review of randomized trials
Individual participant data meta-analysis of randomized controlled trials
PubMed 28969441 · doi:10.1176/appi.ajp.2017.17040472
What was done
Authors conducted a systematic review and individual participant data meta-analysis of 10 comparison studies evaluating a single dose of intravenous ketamine against saline or midazolam controls. The analysis included 167 participants with baseline suicidal ideation. A one-stage mixed-effects multilevel general linear model analyzed clinician-administered (MADRS, HAM-D) and self-reported (QIDS-SR, BDI) suicide-specific items for up to 1 week post-infusion.
What was found
Ketamine rapidly reduced suicidal ideation within 1 day on both clinician-rated and self-reported measures, with moderate to large effect sizes (Cohen's d = 0.48 to 0.85) sustained across all time points up to 1 week. Significant reductions were observed on individual suicide items of the MADRS, HAM-D, and QIDS-SR, but not the BDI. The anti-suicidal effect remained statistically significant after controlling for concurrent changes in overall depressive symptom severity.
Why it matters
This confirms that ketamine provides rapid anti-suicidal effects within 24 hours that last up to one week, demonstrating an action partially independent of broader mood improvements in acute depression.
Limits
The total sample was modest (N=167 pooled across 10 studies), and 1 of 11 identified eligible trials could not be included. Suicidal ideation was measured using single sub-items from depression scales rather than comprehensive, dedicated suicidality instruments. Follow-up ended at 1 week, leaving longer-term safety, sustained efficacy, and impact on actual suicidal behavior unmeasured.
Cited by
- supports Ketamine administration frequently resolves suicidal ideation within the first few hours.