Glutamate and glutamine in the anterior cingulate and thalamus of medicated patients with chronic schizophrenia and healthy comparison subjects measured with 4.0-T proton MRS.

OBJECTIVE This in vivo (1)H magnetic resonance spectroscopy study examined levels of glutamate, glutamine, and N-acetylaspartate in medicated patients with chronic schizophrenia. METHOD Localized in vivo (1)H spectra were acquired at 4.0 T from the left anterior cingulate and thalamus of 21 patients with schizophrenia and 21 comparable healthy volunteers. RESULTS Significantly lower levels of glutamine and glutamate were found in the left anterior cingulate cortex of patients with schizophrenia than in the healthy volunteers. For the schizophrenia patients, the glutamine level in the left thalamus was found to be higher than normal, and there was a significant negative correlation between N-acetylaspartate level and duration of positive symptoms. CONCLUSIONS Since previous studies have found higher than normal levels of glutamine in the left anterior cingulate of never-treated patients, decreased levels of these metabolites in chronic patients could be related to neurodegeneration or the effects of chronic medication.