Sex differences in the prevalence and clinical correlates of autistic features in patients with chronic schizophrenia: a large scale cross-sectional study

Sex differences have been suggested in both schizophrenia (SCZ) and autism spectrum disorder (ASD). This study aims to assess the prevalence and clinical correlates of autistic features in male and female patients with chronic SCZ. A total of 1690 chronic SCZ patients (M/F: 1122/568) were recruited from ten psychiatric hospitals in China. The Positive and Negative Syndrome Scale Autism Severity Score and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were utilised to assess the presence of autistic features and measure cognitive function, respectively. Female SCZ patients had a higher prevalence of autistic features than male SCZ patients. In male patients, those with autistic features exhibited higher illness duration and RBANS scores, but lower years of education. Whereas in female patients, those with autistic features had higher RBANS scores, but lower years of education. Binary logistic regression analysis revealed that years of education, illness duration, visuospatial/constructional abilities, and language were correlated with autistic features in male patients. In female patients, years of education, language, and delayed memory were correlated with the presence of autistic features. Our findings suggest that sex differences exist in the prevalence and clinical correlates of autistic features in chronic SCZ patients.