Re-examining the core features of autism: a comparison of autism spectrum disorder and fetal alcohol spectrum disorder

Background: Autism spectrum disorder (ASD) and fetal alcohol spectrum disorder (FASD) are both characterized by social difficulties, but overall clinical descriptions of the two disorders are different. Method: Twenty-nine children with autism and 33 children with pervasive developmental disorder-not otherwise specified (PDD-NOS) were compared to 29 children with FASD of equivalent age and full-scale IQ. To isolate social deficits that are most unique to ASD, all participants were administered the Autism Diagnostic Observation Schedule (ADOS). Parents of the children completed the Autism Diagnostic Interview-Revised (ADI-R). Results: Difficulties in initiating social interaction, sharing affect, and using nonverbal communication were common in children with ASD but rare in children with FASD. Socially inappropriate behaviors and difficulty with peers were common in both groups. Conclusions: These findings suggest that whereas propensity for social interaction appears to be a differentiating factor between children with ASD and those with non-spectrum disorders, impaired quality of social interaction may be less diagnostically discriminative.