INTRODUCTION
TRD, deaths, depressive, ideation
Over the last half century, worldwide suicide rates have increased by 60%, and suicide accounted for more than 1 million deaths in 2020 (A growing body of evidence has supported the rapid and sustained antisuicidal effect of low-dose ketamine (In a real-world clinical setting, however, TRD and severe suicidal ideation commonly occur together and exacerbate the effects of one another (In the current study, we enrolled 84 patients with TRD and prominent suicidal ideation (MADRS item 10 ≥4) who were randomized to 2 groups receiving a single infusion of either 0.5 mg/kg ketamine or 0.045 mg/kg midazolam. We followed the patients for 2 weeks to assess their depressive and suicidal symptoms. We hypothesized that the low-dose ketamine infusion would exert rapid and sustained antidepressant and antisuicidal effects in patients with TRD and prominent suicidal ideation, particularly among those without severe treatment refractoriness or chronic TRD.