Increased morning cortisol after ketamine treatment for suicidal depression: Exploratory report from a randomized trial.

Depression and its severe outcomes, suicidal ideation and behavior, are exacerbated by stress. A broad literature links dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) stress response system to depression, suicidal ideation and behavior. Our midazolam-controlled clinical trial of subanesthetic, intravenous ketamine infusion for suicidal depressed patients found rapid reduction in suicidal ideation within 24 h. Here we report on an exploratory aim of the trial to investigate relationships of treatment effect and clinical response to HPA axis function via saliva cortisol analysis. Saliva cortisol awakening response was measured at baseline/pre-infusion and 24 h after with samples obtained upon morning awakening and 30 min later. A significant increase in waking cortisol 24 h after ketamine treatment was observed (t(61) = -3.15, p = 0.0025). Baseline to post-infusion increase in waking cortisol had a small to medium, nonsignificant, correlation with decrease in SI (r = -0.25, p = 0.052). These preliminary results need to be replicated but are consistent with studies suggesting increases in cortisol, if not excessive or prolonged, may enhance stress-resilience.