Given the lack of consensual definitions of diagnosis until recently, it is not surprising that the prevalence of Aspergers is unknown, although a rate of 2 to 4 in 10,000 has been reported.
There is little doubt that the condition is more prevalent in boys than girls, with a reported ratio of 9 to 1.
In the past few years, there have been a proliferation of parent support groups organized around the concept of Aspergers, and there are indications that this diagnosis is being given by clinicians much more frequently than even just a few years ago; there are also indications that Aspergers is currently functioning as a residual diagnosis given to normal-intelligence young people with a degree of social disabilities who do not fulfill criteria for autism, overlapping in this way, with the DSM-IV term PDD-NOS.
Possibly the most common usage of the term Aspergers is as synonymous or a replacement to autism in children with normative or superior IQs. This pattern has diluted the concept and reduced its clinical utility. Empirical validation of specific diagnostic criteria is badly needed, although this will have to await reports of rigorous studies employing standard diagnostic procedures, and “validators” truly independent of the diagnostic definition such as neuropsychological, neurobiological and genetic data.