Effect of intravenous ketamine on suicidality in adults with treatment-resistant depression: A real world effectiveness study

Suicidal ideation is a significant symptom associated with mood disorders. Ketamine is an emerging treatment with rapid and robust antidepressant and antisuicidal effects observed in clinical trial populations. Herein we assessed the real-world effectiveness of ketamine in ameliorating suicidality. A retroactive chart analysis of 96 adult TRD patients that received treatment in a private community clinic in Toronto, Ontario was conducted. Suicidality and depressive symptom outcomes were assessed with the Columbia Suicide Severity Rating Scale (C-SSRS) (self-report version) and the Quick Inventory for Depressive Symptomatology Self-Report 16-Item (QIDS-SR16) respectively. The effect of ketamine on suicidal ideation was modelled using generalized estimating equations adjusting for demographic predictors and depressive symptom severity. A mediation analysis was conducted to evaluate the contribution of the antidepressant effects of ketamine on its antisuicidal properties. Mean C-SSRS score significantly decreased following a single ketamine infusion and was indicative of a reduction in suicidality from active to passive suicidal ideation on a group level. Results of the mediation analysis indicated that the antisuicidal effects of ketamine are partially independent of its antidepressant effects. Our study supports the use of ketamine in treating suicidal ideation in a real-world setting with benefits comparable to clinical trials.