Glutamate plus glutamine to GABA ratio as a predictor of ketamine response in treatment-resistant depression: A double-blind, randomized, open-label extension study.
Journal of affective disorders August 15, 2025 Yohei Ohtani, Hideaki Tani, Shiori Honda et al. 3 citations
About 30% of people with treatment-resistant depression respond to ketamine, but reliable predictors of response have been lacking. This study examined whether the ratio of glutamate+glutamine (Glx) to GABA in the dorsal anterior cingulate cortex (dACC) could predict ketamine's effectiveness. In a double-blind randomized trial with an open-label extension involving 30 participants, a higher baseline Glx/GABA ratio in the dACC correlated with greater improvement in depression scores (measured by the HDRS-17). After ketamine treatment, a reduction in this ratio also correlated with symptom improvement. The findings suggest that an excitatory-inhibitory imbalance in the dACC may help predict which patients will benefit from ketamine therapy.