This article is about the classic autistic disorder; some writers use the word autism when referring to the range of disorders on the autism spectrum or to the various pervasive developmental disorders
Autism is a neurodevelopmental disorder characterized by impaired social interaction, verbal and non-verbal communication, and restricted and repetitive behavior. Parents usually notice signs in the first two years of their child’s life. These signs often develop gradually, though some children with autism reach their developmental milestones at a normal pace and then regress. Thediagnostic criteria require that symptoms become apparent in early childhood, typically before age three.