Do autism spectrum disorders affect one's intellectual capacity or just behavior?

See below: It depends upon which part of the autistic spectrum the person is. Asperger patients are of normal intelligence, but the children on the other end, have mental impairment.

Categorical: Asd's are categorical diagnoses based on history, observable behaviors & standardized tests. Intellectual disability is a separate diagnosis of cognitve & adaptive abilities significantly below average before age18. Id co-exists in ~ 65% of people with autism. A person with high-functioning autism or asperger's has an overall iq > 70, though verbal & non-verbal iq's are often highly disparate.

Run the gamut: Autism spectrum disorders run the gamut from from retardation in classic autism to normal intelligence with poor social interaction.