Anomalies of cerebral asymmetry in schizophrenia interact with gender and age of onset: a post-mortem study

In a post-mortem study of cerebral asymmetry in schizophrenia it was found that asymmetry of the length from the frontal pole to the central sulcus measured dorsally over the external surface of the brain on both hemispheres, showed a gender×diagnosis interaction (p=0.002). Female controls had a left-greater-than-right asymmetry, and the male controls had a right-greater-than-left asymmetry. This pattern was reversed in schizophrenia. The converse effect was observed on a similar measure of the occipito-parietal lobes (p=0.028). Significant changes were not seen in measures taken around the lateral surface of the hemispheres. Further, within the patient group, the frontal lobe asymmetry was related to age of onset such that leftward asymmetrical brains were associated with a later age of onset than rightward asymmetrical brains (p=0.0463 for the females; p=0.0162 for the males). The occipito-parietal asymmetry was not related to age of onset. We conclude that the asymmetry of the relative distribution of tissue between frontal and posterior regions of the hemispheres is altered in schizophrenia. The findings also suggest that there is an interaction between gender and cerebral asymmetry that is critical in determining age of onset.