Sex Differences in Social-Communication Function in Children with Autism Spectrum Disorder and Attention-Deficit Hyperactivity Disorder: Data from the Pond Network
Objectives: This study examined potential sex differences in social and communication function in ASD and ADHD.
Methods: 115 youth with ASD, 172 youth with ADHD and 63 typically developing controls (age range 8-12 years, 75% males) were recruited from the Province of Ontario Neurodevelopmental Disorder (POND) Network. Social and communication function were assessed using the communication, leisure and social skill areas of the Adaptive Behaviour Assessment Scale-Second Edition (ABAS-II). To test for sex differences, a logistic regression was performed on the proportion of positive items for each skill area (i.e., communication, leisure and social), controlling for age and sex.
Results: Significant sex by age interactions were seen within ASD on the communication (p=0.005), leisure (p=0.003) and social skill areas (p<0.0001). In all three areas, lower scores were found in females compared to males at the age of 12, despite females performing better than males at the age of 8. There were significant sex by age interactions in the social (p=0.02) and leisure (p= 0.0005) domains between those with ASD and typically developing controls, with typically developing females showing better scores at older ages. Sex by age interactions were significant between ASD and ADHD on the social (p=0.009) and leisure domains (p<0.0001), as females with ADHD consistently scored higher on social skills than males across all ages, unlike those with ASD. Sex differences across age in the social domains for ADHD were similar to those in the typically developing group.
Conclusions: Sex differences in social and communication domains were observed between ASD and ADHD, and typically developing controls, with females with ASD performing worse than males at older ages, despite earlier advantages, potentially suggesting a female –specific phenotype in ASD. This has implications on development of treatments plans that target social function in females with ASD. Furthermore, these findings reinforce the need to take a developmental/longitudinal approach to understanding sex differences.