DECREASED REGIONAL CORTICAL GRAY-MATTER VOLUME IN SCHIZOPHRENIA

Objective: The authors hypothesized that cortical gray matter volume r eduction in schizophrenia is greatest in the heteromodal association c ortex. This area comprises a highly integrated, reciprocally interconn ected system that coordinates higher order cortical functions. Method: Total brain and regional gray matter volumes were calculated in 46 sc hizophrenic patients and 60 age and sex-matched comparison subjects by using magnetic resonance images. Disease specificity was examined by assessing 27 patients with bipolar disorder. Approximations to the dor solateral prefrontal cortex, inferior parietal lobule, and superior te mporal gyrus were selected as regions of interest for the heteromodal association cortex. Occipital and sensorimotor areas were used as comp arison regions to test the hypothesis for regional specificity. Result s: Gray matter volume was reduced in schizophrenic patients in index r egions even after covariance for overall brain volume, sex, and age. B ipolar disorder patients did not exhibit heteromodal gray matter reduc tion. Comparison regions did not differ among the three groups. Global gray matter volume was not different among groups after covariance fo r global brain volume. Comprehensive individual region post hoc analys is found no additional gray matter differences. Conclusions: These fin dings support the theory of disproportionate reduction of gray matter volume in the heteromodal association cortex specific to schizophrenia .