Background: The glutamate N-methyl-D-aspartate receptor antagonist ketamine has a rapid antidepressant effect in major depressive disorder (MDD) patients. Though, the ketamine's possible mechanism of action has been debated the main hypothesis was focused around glutamate.
Methods: A proton short-echo MR Spectroscopy was utilised to examined three brain regions Anterior Cingulate Cortex, Hippocampus and Raphe nuclei before and 24-hours after treatment. 28 Selective Serotonin Reuptake Inhibitor resistant MDD patients were randomized to double blind monotherapy with 0.5 mg/kg ketamine or placebo infusion.
Results: glutamate correlates with depression symptoms severity in ACC and HC in opposing ways in ketamine group.