Hemispheric asymmetry and psychopathological dimensions in drug-free patients with schizophrenia

Several neuropsychological models of schizophrenia have regarded the syndrome as a disorder of the left hemisphere. However, discrepant experimental findings have been reported. It has been proposed that the different psychopathological dimensions of the syndrome are associated with distinct patterns of hemispheric imbalance. The present study was aimed at exploring relationships of psychopathological dimensions of schizophrenia with fronto- and temporo-hippocampal functioning of either hemisphere in 42 drug-free patients with a DSM-III-R diagnosis of schizophrenia. For the negative dimension, an inverse correlation with the performance on a verbal conditional associative task was found, consistent with the presence of a left fronto-hippocampal impairment in this dimension. As to the positive dimension, our results showed a direct correlation with perseveration on a verbal self-ordered pointing task, suggesting a hyperactivation of the left-hemisphere in this dimension. The disorganisation was found to be associated with a faster execution of a spatial memory task, probably reflecting increased perceptual priming and a right temporo-hippocampal disinhibition.