Sex Differences in Social Cognition, Executive Functioning and Repetitive Behaviours in Children and Adolescents with ASD

Background: One of the most replicated findings in the field of Autism Spectrum Disorder (ASD) research is a male preponderance. Recent studies suggest that the frequently stated 4:1 male to female ratio is influenced by many biases including differences in symptom presentation, IQ, and diagnostic criteria. Females with ASD have been observed to show increased social behaviour, higher language ability and less repetitive behaviours, relative to their male counterparts. These findings collectively suggest that the skewed sex ratio may be due to males exhibiting more disruptive and stereotypical symptoms of ASD that warrant clinical attention, relative to females. Females who have ASD and higher IQs may thus ‘mask’ their ASD symptomology, and diagnosis may be missed altogether, which in turn contributes to the skewed sex ratio in this population. Investigating sex differences in ASD symptomology contributes to better understanding and characterization of the female ASD phenotype, which in turn has implications for diagnosis and the treatment of ASD. 

Objectives: To investigate sex differences in executive functioning, social skills and repetitive behaviours in children and adolescents with and without ASD. 

Methods: We collected data in 187 children and adolescents: with ASD (N=96, M=10.54­+2.32 years, IQ=100.89+15.46; females only: N=14, M=11.07+2.22 years, IQ=99.33+15.47) and typically developing controls (N=91, M=11.02+2.55 years, IQ=113.36+12.19; females only: N=23, M=10.39+2.25 years, IQ=114.05+14.67). For all participants, parents filled out the parent form of the Behavior Rating Inventory of Executive Function (BRIEF), Social Responsiveness Scale (SRS), and Repetitive Behaviour Scale – Revised (RBS-R). It should be noted that all participants, including the clinical sample, were high-functioning as they were recruited as part of a larger neuroimaging study. 

Results: A two-way ANOVA with IQ as a covariate showed a main effect of group for all SRS, BRIEF and RBS-R variables (p<0.001) as well as a significant group by sex interaction on the Social Awareness subscale of the SRS (F(1, 156) = 6.38, ‪p=0.01). Females with ASD were more impaired in social ‪awareness relative to males with ASD, whereas in the control group scores reflected a greater social awareness in females relative to males. Sex effects were also found in the Restrictive and Repetitive Behaviour subscale of the SRS (F(1, 156) = 5.12, p= 0.03), with males showing consistently greater restricted and repetitive behaviours relative to females.  

Conclusions: These preliminary results suggest that impairment in social awareness is particularly heightened in female children and adolescents with ASD. Reduced social awareness in child and adolescent females with ASD reflect difficulties in picking up social cues during social interactions. Our finding highlights that impaired social awareness may be a defining trait in the female ASD phenotype.