A proton MRSI study of brain N-acetylaspartate level after 12 weeks of citalopram treatment in drug-naive patients with obsessive-compulsive disorder.

OBJECTIVE: Reductions in the level of N-acetylaspartate within subcortical structures of patients with obsessive-compulsive disorder (OCD) have been reported in several studies. However, there have been, as yet, no reports regarding N-acetylaspartate levels in the prefrontal cortex of adult drug-naive OCD patients. The authors used proton magnetic resonance spectroscopic imaging ((1)H-MRSI) to investigate regional N-acetylaspartate level abnormalities and changes after 12 weeks of pharmacotherapy with citalopram in drug-naive OCD patients. METHOD: Thirteen drug-naive OCD patients and 13 age- and sex-matched healthy comparison subjects were included in this study. N-acetylaspartate levels (obtained from ratios of N-acetylaspartate with creatine, choline, and creatine plus choline) in the prefrontal cortex, parietal cortex, anterior cingulate, posterior cingulate, frontal white matter, and parietal white matter were measured by (1)H-MRSI. In OCD patients, measurements were taken before and after 12 weeks of citalopram treatment. Correlations between N-acetylaspartate concentrations in regions of interest and clinical measures were also assessed. RESULTS: Drug-naive OCD patients exhibited significantly lower N-acetylaspartate levels in the prefrontal cortex, frontal white matter, and anterior cingulate at baseline than did comparison subjects. Significant increases in N-acetylaspartate level were detected in the prefrontal cortex and frontal white matter in OCD patients after 12 weeks of citalopram treatment. CONCLUSIONS: These data suggest that reductions in neuronal viability occur in the frontal region of OCD patients and that these reductions may be partly reversible.

Decreased caudal anterior cingulate gyrus volume and positive symptoms in schizophrenia.

The anterior cingulate gyrus is a heterogeneous region that has specialized subdivisions with respect to its cytoarchitecture, function and connectivity. The aim of this study was to examine the morphological changes of the caudal subdivision of the anterior cingulate gyrus in the context of the cortico-striatal-thalamo-cortical circuitry of schizophrenia and their relationship to clinical symptoms. Accordingly, we measured the volumes of the caudal and rostral anterior cingulate gyrus, the orbitofrontal cortex, the caudate and the thalamus by magnetic resonance imaging in age- and sex-matched groups, which consisted of 22 patients with schizophrenia and 22 normal volunteers. The clinical symptoms of schizophrenia patients were obtained using the Positive and Negative Syndrome Scale. Volumetric reduction of the right caudal anterior cingulate gyrus was observed in patients with schizophrenia as compared with the normal controls. Furthermore, a smaller volume of the caudal anterior cingulate gyrus was significantly correlated with more severe positive symptoms of schizophrenia. Thus, these findings suggest that a volumetric abnormality of the caudal anterior cingulate gyrus in schizophrenia may be related to positive symptoms and possibly involved in the pathophysiology of schizophrenia.