Evaluating Sex and Age Differences in ADI-R and ADOS Scores in a Large European Multi-site Sample of Individuals with Autism Spectrum Disorder

Research on sex-related differences in Autism Spectrum Disorder (ASD) has been impeded by small samples. We pooled 28 datasets from 18 sites across nine European countries to examine sex differences in the ASD phenotype on the ADI-R (376 females, 1763 males) and ADOS (233 females, 1187 males). On the ADI-R, early childhood restricted and repetitive behaviours were lower in females than males, alongside comparable levels of social interaction and communication difficulties in females and males. Current ADI-R and ADOS scores showed no sex differences for ASD severity. There were lower socio-communicative symptoms in older compared to younger individuals. This large European ASD sample adds to the literature on sex and age variations of ASD symptomatology

Does Gender Moderate Core Deficits in ASD? An Investigation into Restricted and Repetitive Behaviors in Girls and Boys with ASD

Due to the uneven gender ratio of autism spectrum disorders (ASD), girls are rarely studied independently from boys. Research focusing on Restricted and Repetitive Behaviors (RRBs) indicates that above the age of six girls have fewer and/or different RRBs than boys with ASD. In this study we investigated whether girls and boys with ASD demonstrated similar rates and types of RRBs in early childhood, using discrete observational coding from a video-taped play interaction. Twenty-nine girls with ASD were matched to 29 boys based on ASD severity. While boys in our sample demonstrated a greater frequency of RRBs, this was not significant and our findings indicate that girls and boys under five are more similar than dissimilar on this core deficit. However our data also revealed a trend toward gender-differential growth trajectories – a finding worthy of further investigation in larger samples