TPE2 wrote:
If I am correct, the diagnosis criteria used before the inclusion of AS in DSM (Szatrmari, Gilbberg, etc.) did not have any point of "average or above average intelligence" (in other words, individuals with mental retardation could be diagnosid using these criteria), what, of course, made the average IQ of the individuals diagnosed according these criteria lower than of the individuals diagnoses according to the DSM.
The DSM-IV-TR doesn't specifically exclude mental retardation, as long as it's not apparent in the first few years of life (only "mild" retardation though; autism and more severe mental retardation/verbal ability is always evident early, unlike AS, which is usually first seen in the beginning of the school years when the individual starts interacting outside of the family). The DSM is specifically mentioned in the book as the criteria used. A problem arises when you have people with Autism, who go on to develop normal speech and cognitive ability when they start school (about 50% or so nowadays), who tend to be of a similar appearance to the latter (the AS/HFA thingy).
The point being, that people with Asperger's are effectively within the normal continuum of IQ scores from birth, unlike nearly all with Autism.