Modulation of Magnetic Resonance Spectroscopy Levels of Glutamate and GABA by Ketamine in Treatment-Resistant Depression.
Journal of neuroscience research January 1, 2026 Stephanie Njau, Artemis Zavaliangos-Petropulu, Shantanu Joshi et al.
In people with treatment-resistant depression, a single low-dose ketamine infusion increased glutamate levels in the dorsal anterior cingulate cortex only in those who responded to treatment, and lower pre-treatment glutamate levels predicted greater improvement in depression scores. GABA levels did not change after treatment. Other brain metabolites linked to neuronal health and metabolism also increased. These findings suggest that ketamine's antidepressant effect involves sustained enhancement of glutamate-related neurotransmission and that baseline glutamate levels may help predict who will benefit from ketamine.