The Effect of a Single Dose of Intravenous Ketamine on Suicidal Ideation: A Systematic Review and Individual Participant Data Meta-Analysis

Suicide is a public health crisis with limited treatment options. The authors conducted a systematic review and individual participant data meta-analysis examining the effects of a single dose of ketamine on suicidal ideation. METHOD: Individual participant data were obtained from 10 of 11 identified comparison intervention studies that used either saline or midazolam as a control treatment. The analysis included only participants who had suicidal ideation at baseline (N=167). A one-stage, individual participant data, meta-analytic procedure was employed using a mixed-effects, multilevel, general linear model. The primary outcome measures were the suicide items from clinician-administered (the Montgomery-Åsberg Depression Rating Scale [MADRS] or the Hamilton Depression Rating Scale [HAM-D]) and self-report scales (the Quick Inventory of Depressive Symptomatology-Self Report [QIDS-SR] or the Beck Depression Inventory [BDI]), obtained for up to 1 week after ketamine administration.

Ketamine rapidly (within 1 day) reduced suicidal ideation significantly on both the clinician-administered and self-report outcome measures. Effect sizes were moderate to large (Cohen's d=0.48-0.85) at all time points after dosing. A sensitivity analysis demonstrated that compared with control treatments, ketamine had significant benefits on the individual suicide items of the MADRS, the HAM-D, and the QIDS-SR but not the BDI. Ketamine's effect on suicidal ideation remained significant after adjusting for concurrent changes in severity of depressive symptoms.