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

The data were pooled from 18 sites and 28 datasets that were not fully matched for assessment methods, diagnostic procedures or recruitment settings. The study was cross-sectional, so age differences compared different people at different ages rather than following the same people over time. Only 464 of 2684 participants were female, so sex comparisons relied on a relatively small female subgroup. ADOS participants were not equally distributed across modules, and the majority received Module 1 for preverbal children or children using single words, which limits age-related conclusions from ADOS data. When non-verbal IQ was included, the sample became smaller and the early repetitive behaviour sex difference dropped to a trend after correction. There were no formal exclusions for other psychiatric or developmental conditions, so the pooled sample may have had varied co-occurring problems.

Funders named were the Innovative Medicines Initiative Joint Undertaking, Instituto de Salud Carlos III/Fondo Investigaciones Sanitarias, Fundació la Marató de TV3, Wellcome Trust, Medical Research Council, and the Research for Patient Benefit Programme. The supplied text does not report author conflict-of-interest declarations.

Do not conclude that girls with autism have milder social communication difficulties. Current social communication and observation scores were similar between males and females, and the sex difference was limited to early reported repetitive behaviours, which weakened when non-verbal IQ was considered.