Subtype-associated metabolite differences in the temporal lobe in schizophrenia detected by proton magnetic resonance spectroscopy

Brain imaging studies have indicated that the medial temporal lobe function s aberrantly in schizophrenic patients. Both diagnostic subtype and gender may affect functional and morphologic abnormalities in this region. We inve stigated subtype- and gender-associated differences in metabolites in the l eft medial temporal lobe in 40 medicated schizophrenic patients by proton m agnetic resonance spectroscopy and compared findings with those in 40 healt hy control subjects. Peaks corresponding to N-acetylaspartate (NAA), cholin e-containing compounds (Cho), creatine-phosphocreatine (Cr), and inositol w ere measured. Schizophrenic patients showed a decrease in the NAA/Cr ratio in the left medial temporal lobe, and patients with the disorganized subtyp e of illness showed significantly lower NAA/Cr and Cho/Cr ratios than those with paranoid schizophrenia. The NAA/Cr ratio in patients with the undiffe rentiated subtype also was significantly lower than in the paranoid subtype . No significant associations were observed between metabolite ratios and c linical symptom scores, age at onset of illness, or gender. These findings suggest that patients with the disorganized and undifferentiated subtypes h ave greater impairments in neuronal integrity or function in the left media l temporal lobe than patients with other subtypes of schizophrenia.