Spencer C. Evans, Andrea D. Boan, Catherine Bradley, Laura A. Carpenter

Autism spectrum disorder (ASD) is diagnosed more often in boys than in girls; however, little is known about the nature of this sex/gender discrepancy or how it relates to diagnostic assessment practices. This study examined the performance of the Social Communication Questionnaire (SCQ) in screening for ASD among boys and girls. Data were drawn from the South Carolina Children's Educational Surveillance Study, a population-based study of ASD prevalence among children 8-10 years of age. Analyses were conducted using SCQ data from 3,520 children, with direct assessment data from 272 with elevated SCQ scores. A bifactor model based on the Diagnostic and Statistical Manual of Mental Disorders's (5th ed.) two ASD symptom domains fit the data well and performed slightly better for girls. In the general population sample, girls exhibited fewer social communication/interaction and restricted-repetitive behavior symptoms than boys. In the direct assessment sample, however, girls with ASD showed greater impairment in social communication/interaction than boys with ASD. Items pertaining to social communication/interaction problems at ages 4-5 were among the most diagnostically efficient overall and particularly for girls. Similarly, receiver operating characteristic analyses suggested that the SCQ performs adequately among boys and well among girls. Results support the use of the SCQ in screening for ASD but do not indicate sex/gender-specific cutoffs. Girls with ASD may exhibit pronounced intraindividual deficits in social communication/interaction compared to male peers with ASD and female peers without ASD. Although more research is needed, careful attention to social communication/interaction deficits around 4-5 years of age may be especially useful for assessing ASD in girls.