Ketamine Metabolite Plasma Levels As Potential Blood Markers of Ketamine Efficacy in Treatment Resistant Depression

Introduction Accumulating evidence has revealed robust fast-acting antidepressant effects of ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist, in patients with treatment-resistant depression (TRD). However, considering that clinical responses can only be observed in 50% of TRD patients [1], treatment decisions lack predictors on patients’ individual benefit.