At issue: Sex and gender in schizophrenia

Using data collected in a study of sex differences in schizophrenia, I undertook this study to show the utility of distinguishing between sex and gender in the study of schizophrenia. Schizophrenia and schizoaffective disorder were combined to yield 213 patients (141 men, 72 women). There were 98 healthy controls (41 men, 57 women). The relative contributions of sex and gender to the prediction of age of first hospitalization and neuropsychological functioning were examined in linear regression analyses. Sex, but not gender, was a significant predictor of age at first hospitalization, even when controlling for illness severity. Among patients, sex and gender significantly contributed to the prediction of neuropsychological performance, beyond the contributions of education, age, and illness severity. Comparable results were found among healthy controls, although gender was significant only for women. For both healthy subjects and patients, more frequent endorsement of female typical social roles predicted better neuropsychological functioning. Being female also predicted higher neuropsychological scores in patients. The findings suggest that some aspects of schizophrenia study, such as the disorder's onset, may be best pursued from a more biological (sex difference) perspective, while a sociocultural (gender difference) perspective may best serve other aspects of study, such as neuropsychological functioning.