The diagnosis of autism spectrum disorders (ASDs) in older children with intellectual disabilities (IDs) is challenging because of overlap in symptomatology and the high comorbidity of these disorders. On the basis of a sample of 89 older children with IDs (aged 6—15 years) referred to an ASD clinic, semistructured parent interviews were used to investigate the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.) diagnostic criteria that differentiated children with ASDs from those without ASDs. Diagnostic criteria related to impaired social interactions, stereotyped or idiosyncratic language, poor conversational skills, lack of pretend and imitative play, and restricted or narrowed interests were related to ASD diagnoses. The findings of this study have implications for improving ASD diagnostic evaluations in children with IDs.
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