Sex-onset effects on neuropsychological function in schizophrenia.

Heterogeneity of results continues to hamper schizophrenia research. The examination of sex differences in the effort to reduce this heterogeneity has had mixed results in neuropsychology. We have begun to examine the validity of both sex and onset age to define early-onset male and late-onset female prototypes of the disorder. Extensive neuropsychological assessment of 191 schizophrenia/schizoaffective patients was conducted. Analysis of performance scores revealed a significant pattern reflecting poorer performance and less lateralized function in early-onset men and late-onset women compared with late-onset men and early-onset women. The discussion addresses the etiological implications of these findings.