Evidence for altered cerebellar vermis neuronal integrity in schizophrenia

To determine if there was evidence for altered neuronal integrity in the ce rebellar vermis of patients with schizophrenia, the authors measured N-acet yl-aspartate (NAA, a putative neuronal/axonal market) using in vivo proton magnetic resonance spectroscopic imaging (H-1-MRSI) in 20 chronically medic ated mate patients with schizophrenia and 15 male comparison subjects. Rela tive contributions of cerebrospinal fluid, gray matter, and white matter to each MRSI voxel were determined using an MRI tissue segmentation technique . The percentage of tissue was used as a co-variate to determine the extent to which tissue composition contributed to NAA differences. Schizophrenic patients showed significantly decreased NAA and creatine in the anterior ce rebellar vermis, independent of differences in voxel tissue composition. Ce rebellar NAA levels in control subjects were also significantly correlated with the amount of cerebellar gray matter enclosed in the MRSI voxels, but not in the schizophrenic group. There was no association between cerebellar NAA measures and duration of illness or neuroleptic dose in chlorpromazine equivalents. Reduced NAA in the anterior cerebellar vermis of mate patient s with schizophrenia supports the hypothesis that cerebellar dysfunction co ntributes to the pathophysiology of schizophrenia. Furthermore, the lack of a significant correlation between NAA and the amount of cerebellar gray ma tter in MRSI voxels in the schizophrenic group suggests that NAA levels in both cerebellar gray and white matter are similar in schizophrenic patients , and are presumed to be the result of reduced NAA concentration in the cer ebellar gray matter. (C) 2001 Published by Elsevier Science Ireland Ltd.