247. DOES EXCITATORY/INHIBITORY BALANCE PREDICT KETAMINE RESPONSE IN TREATMENT-RESISTANT DEPRESSION? A DOUBLE-BLIND RANDOMIZED CONTROLLED TRIAL WITH 1H-MRS
The International Journal of Neuropsychopharmacology August 1, 2025 Yuko Ohtani, Hiroe Tani, Shiori Honda et al.
A higher baseline ratio of glutamate+glutamine (Glx) to GABA in the dorsal anterior cingulate cortex predicted greater improvement in depressive symptoms after ketamine treatment in adults with treatment-resistant depression. In the ketamine group, a reduction in this Glx/GABA ratio correlated with symptom improvement, but no such association appeared in the placebo group. The findings suggest that the balance between excitatory and inhibitory neurotransmission in this brain region may serve as a biomarker for predicting antidepressant response to ketamine.