Ketamine Associated ACC GABA and Glutamate Change and Depression Remission:

This is a feasibility study and the goal of this project is to evaluate whether peak ACC GABA and glutamate, quantified as a CSF-corrected absolute concentration percent change from baseline, is associated with clinical remission, Montgomery Asberg Depression Rating Scale (MADRS) total score of \<10, to the anti-glutamatergic antidepressant ketamine. As MRS is expensive, we also aim to study a correlation between change in peripheral metabolites (GABA and glutamate) and central GABA and glutamate levels.

Aims: This feasibility study aims to better understand the neurobiology of major depression and how ketamine may therapeutically impact brain function. This research may provide important insights into the mechanism of ketamine response, thus, potentially increasing the likelihood of successful treatment interventions and decrease the number of ineffective treatments and/or risk for serious side effects. SPECIFIC AIMS: Utilizing novel dynamic sliding-window functional MR spectroscopy (fMRS) and liquid chromatography-mass spectrometry (LCMS), we aim to evaluate the relationship between GABA and glutamate (central-baseline to peak and peripheral-baseline to 24 hours) levels with a change in depression symptoms (baseline to 24 hours), after a single infusion of intravenous (IV) ketamine, in subjects with treatment-resistant depression (TRD).