Measuring suicidal behavior in the era of rapid-acting antidepressants: A systematic review of ketamine studies

Abstract

Assessment measures for suicidal behavior range from depression scales to longer suicide-specific instruments. In this review, we systematically summarize and discuss the currently used instruments for assessing suicidal behavior in the context of ketamine and its enantiomers. We searched Medline/PubMed, Embase, and PsycINFO databases for ketamine (and its enantiomers) human studies exploring this drug's antisuicidal effects on major depressive disorder patients, published from February 2000 to June 2023. Forty-six studies were included, identifying 16 assessment tools, mostly explicit and clinician-rated measures. Prominent tools included the Montgomery-Åsberg Depression Rating Scale (MADRS), Hamilton Depression Rating Scale (HAM-D), and both the clinician and patient-rated Beck Scales for Suicide Ideation (SSI and BSS). With the exception of the Suicide Ideation and Behavior Assessment Tool (SIBAT), to the best of our knowledge, no other instrument that assesses suicidality seems to be specifically developed for measuring treatment response in rapid-acting antidepressants trials. Most scales have been validated in conventional antidepressant or psychotherapy contexts, though, for MADRS, as well as for SSI, BDI, and HAM-D, efforts have been made towards investigating their psychometric properties in the field of rapid-acting antidepressants. The heterogeneity of suicidal behavior assessment in ketamine studies may hinder adequate comparisons between them. Although there does not seem to be a universally preferable instrument for measuring suicidal behavior to date, the MADRS potentially emerges as an adequately recommended choice.