Schizophrenia and temporal lobe asymmetry - A post-mortem stereological study of tissue volume

Background A previous report by Crow of a left-sided increase in temporal h orn volume in schizophrenia implies a left-sided loss of tissue. Aims To elucidate the structural nature of schizophrenia. Method The volume of grey matter in the temporal pole and inferior, middle and superior temporal gyri was measured, in addition to the total volume of grey and white matter, in the temporal lobes of the brains of 29 patients with schizophrenia and 27 controls. Results We found a significant left-sided reduction in the superior tempora l gyrus in both males and females with schizophrenia, which was related to increasing age of onset in the males. The total volume of temporal lobe gre y and white matter was also significantly reduced. Although being more mark ed on the left than the right, the lateralisation for these total grey and white measures (by contrast with the superior temporal gyrus alone) did not attain formal statistical significance. Conclusions Confirmation of a lateralised reduction in the superior. tempor al gyrus, which is differentially related to age of onset according to gend er, adds to evidence that the changes in schizophrenia are in systems that are lateralised. The findings implicate language as the relevant function. Declaration of interest Funding received from the Medical Research Council.