Asperger’s differs from Autistic Disorder in that impairment is primarily within the domain of social interactions. No significant delay in the development of other adaptive behaviour, cognition, and language. Stereotypy or repetitive patterns of behavior or rituals must also be present. This disorder tends to be diagnosed later, usually after 3 years of age. This may be due to the characteristics being less noticeable, or the disorder has a later age onset. There has not been much research on this however the most relevant work to date, are studies that included persons with autism characterized as "high functioning", persons referred specifically due to difficulties in social interaction, or persons labeled "with autistic features" or PDD NOS.
