Modeling the interplay of age at onset and sex on cognition in Schizophrenia

Cognition remains one of the most critical features of the schizophrenia. A wide range of factors has been associated to neurocognition and, among these, sex and age of onset are two of the most consistently reported to influence the functional and cognitive outcome. This work aims to evaluate the effects of sex and age of onset and their interaction on cognition in 419 subjects with schizophrenia. Analyses of variance and analyses of covari-ance were performed to evaluate the effect of sex and age at onset on cognition. To model the possible interaction sex-onset on cognition, a separate slope regression analysis was performed. Analyses of variance showed sig-nificant differences between sexes for age and age at onset, both significantly higher among females, as well as for Executive Functions, with higher performance among males. When compared according to age at onset, late -onset patients performed better than both early-and intermediate-onset ones in Verbal Memory subtest, with a significant effect of length of illness. Moreover, early-onset patients showed a significantly lower IQ compared to both intermediate and late-onset ones, with no significant effect of length of illness. Finally, the separate slope regression revealed a significant interaction between sex and age at onset, with early-onset being associated to a worse global cognition only among male patients. Our finding of a significant sex-onset interaction effect on neurocognition sheds new light on the complex issue of cognitive heterogeneity in schizophrenia. Our data may help towards the development of personalized programs for preventive and rehabilitative purposes.

Automated summary

Sex and age of onset are crucial factors influencing cognition in schizophrenia. Females have higher age and age of onset, while males perform better in executive functions. Late-onset patients have better verbal memory performance, while early-onset patients have lower IQ. There is an interaction effect between sex and age at onset, with early-onset being associated with worse global cognition only in male patients.