Ketamine effects on brain GABA and glutamate levels with 1H-MRS: relationship to ketamine-induced psychopathology

Preclinical studies suggest that ketamine-induced psychopathology is mediated, in part, by increased glutamate release, hypothesized to occur via inhibition of GABAergic interneurons. Using proton magnetic resonance spectroscopy (1H-MRS), we tested this hypothesis in healthy humans. Ketamine increased anterior cingulate cortex glutamate levels, which correlated with the degree of positive psychotic symptoms. Ketamine did not affect subcortical gamma-aminobutyric acid (GABA) levels.