Sex Differences in Social Cognition, Executive Functioning and Restricted and Repetitive Behaviours across Development in ASD

Background: One characteristic of Autism Spectrum Disorder (ASD) is a male preponderance, with a 4:1 male to female ratio frequently cited in current literature. However, recent research has indicated that this ratio may be influenced by biases towards males in terms of symptom presentation, diagnostic criteria and intellectual functioning. Relative to males with ASD, females with ASD have been shown to demonstrate increased social behaviour, greater language ability and reduced repetitive behaviours. These findings indicate that the current diagnostic criteria for ASD may not be sensitive for ASD in females and may be biased in favour of more disruptive and stereotypical behaviour. Thus, investigating differences in the presentation between males and females with ASD may lead to a better understanding and characterization of the female ASD phenotype, which in turn, has important clinical implications in terms of diagnosis and treatment.

Objectives: The present study characterized sex differences in everyday executive functioning, social cognition and restricted and repetitive behaviours across three age cohorts, children, adolescents and young adults, with ASD.

Methods: We recruited 187 children and adolescents with ASD (N=96, M=10.54+2.3 years, IQ=100.9+15.4; females only: N=14, M=11.07+2.2 years, IQ=99.3+15.4), typically developing children and adolescents (N=91, M=11.02+2.5 years, IQ=113.4+12.2; females only: N=23, M=10.39+2.2 years, IQ=114.0+14.7) and 16 adults with ASD (mean = 27.9+4.6; IQ = 112.4+19.7; 8 females). Informants filled out measures of executive functioning, social cognition and repetitive behaviour, as assessed by the Behavior Rating Inventory of Executive Function (BRIEF; Parent/Relative/Other Form), Social Responsiveness Scale (SRS; Parent Rating Scale), and Repetitive Behaviour Scale – Revised (RBS-R), respectively.

Results: To investigate overall group effects on executive functions, social responsiveness and repetitive behaviours, MANCOVAs were conducted with all BRIEF, SRS and z-scored RBS-R subscales, controlling for IQ. Informants rated males and females with ASD as having greater difficulty in executive functioning, social responsiveness and repetitive behaviours relative to their typically developing peers. Preliminary analyses further indicated that female children and adolescents with ASD had more difficulty with the ability to interpret social cues (p = 0.03) and stereotypical behaviours or highly restricted interests (p = 0.006).

Conclusions: Difficulty with the ability to interpret social cues carries profound implications in terms of the ability to successfully engage in social interactions. Our preliminary results suggest that impairment in social cognition, specifically the interpretation of social cues and stereotypical behaviours or highly restricted interests, is particularly heightened in female children and adolescents with ASD, relative to their male counterparts. Thus, females with ASD may exhibit greater impairment in social cognition to meet diagnostic criteria for ASD, particularly in terms of cognitive-interpretive aspects of reciprocal social behaviour. Furthermore, these differences are present in early childhood. Data analyses are ongoing to further explore sex differences in executive functioning, social skills and repetitive behaviours in children, adolescents and adults with and without ASD.