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

A previous report by Crow of a left-sided increase in temporal horn volume in schizophrenia implies a left-sided loss of tissue. To elucidate the structural nature of schizophrenia. 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. We found a significant left-sided reduction in the superior temporal 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 grey and white matter was also significantly reduced. Although being more marked 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. Confirmation of a lateralised reduction in the superior temporal gyrus, which is differentially related to age of onset according to gender, adds to evidence that the changes in schizophrenia are in systems that are lateralised. The findings implicate language as the relevant function.