Age at onset and sex differences in corpus callosum area in schizophrenia.

Previous research on neuropsychological function among schizophrenia patients suggests that typical onset males (first psychiatric hospital admission before age 25) and typical onset females (first admission after age 25) may exhibit less lateralization of behavioral function ('hypolateralization') than atypical onset males and atypical onset females. To explore whether these differences were reflected in corpus callosum area, brain morphometric data from a large sample of subjects diagnosed with schizophrenia were analyzed. Typical onset females and typical onset males were compared to atypical onset females and atypical onset males on corpus callosum area. While neither sex nor onset effect on total corpus callosum area was statistically significant, analysis of standard subregions of the corpus callosum revealed a significant interaction effect on the posterior 20% area of the corpus callosum, with typical onset women having particularly large corpora callosa. The anterior 50% area did not differ among the groups. The results are discussed in terms of the role of anomalies in the integration and hemispheric transfer of information as underlying mechanisms of schizophrenia.