Glutamate and glutamine measured with 4.0 T proton MRS in never-treated patients with schizophrenia and healthy volunteers

Objective: This in vivo H-1 magnetic resonance spectroscopy study examined levels of glutamate, glutamine, and N-acetyl-aspartate in patients experiencing their first episode of schizophrenia. Method: Localized in vivo H-1 spectra were acquired at 4.0 T from the left anterior cingulate and thalamus of 21 never-treated patients with schizophrenia and 21 comparable healthy volunteers. Results: The level of glutamine was significantly higher in the left anterior cingulate cortex and thalamus of the patients with schizophrenia than in the healthy subjects. No differences were found between groups in the levels of other metabolites in the anterior cingulate or thalamus. Conclusions: Higher than normal glutamine levels in the left anterior cingulate and thalamus provide in vivo evidence of greater than normal glutamatergic activity proposed by glutamatergic models of schizophrenia. In contrast to other studies in chronically ill patients, no differences were seen in the levels of N-acetylaspartate in either location, suggesting that the findings in patients with chronic schizophrenia may be related to the effect of medication or the progression of the illness.