Ketamine: Review and meta-analysis
Wilkinson et al4 conducted a systematic review and individual participant data meta-analysis of 11 similar comparison intervention studies examining the effects of ketamine in reducing suicidal thoughts.
2. Wilkinson ST, Ballard ED, Bloch MH, et al. The effect of a single dose of intravenous ketamine on suicidal ideation: a systematic review and individual participant data meta-analysis. Am J Psychiatry. 2018;175(2):150-158.
Study design
- Review of 11 studies of a single dose of IV ketamine for treatment of any psychiatric disorder. Only comparison intervention trials using saline placebo or midazolam were included:
- Individual patient-level data of 298 patients were obtained from 10 of the 11 trials. Analysis was performed on 167 patients who had suicidal ideation at baseline.
- Results were assessed by clinician-administered rating scales.
Outcomes
- Ketamine reduced suicidal ideation more rapidly compared with control infusions as assessed by the Montgomery-Åsberg Depression Rating Scale (MADRS) and HAM-D, with significant benefits appearing on Day 1 and extending up to Day 7. The mean MADRS score in the ketamine group decreased to 19.5 from 33.8 within 1 day of infusion, compared with a reduction to 29.2 from 32.9 in the control groups.
- The number needed to treat to be free of suicidal ideation for ketamine (compared with control) was 3.1 to 4.0 for all time points in the first week after infusion.
Conclusion
- This meta-analysis provided evidence from the largest sample to date (N = 298) that ketamine reduces suicidal ideation partially independently of mood symptoms.
While the anti-suicidal effects of ketamine appear to be robust in the above studies, the possibility of rebound suicidal ideation remains in the weeks or months following exposure. Also, these studies only prove a reduction in suicidal ideation; reduction in suicidal behavior was not studied. Nevertheless, ketamine holds considerable promise as a potential rapid-acting agent in patients at risk of suicide.
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