Formally called Autistic Disorder, autism, like Asperger’s Disorder, is a pervasive developmental disorder. The symptoms of autism include markedly abnormal social interaction and communication, and a restricted range of activities and interests. These are the same symptoms as Asperger’s Disorder, so how are the two disorders different?
Signs of autism start far earlier than those of Asperger’s Disorder and allow for diagnosis to be made usually by age two to two and a half. In contrast, the symptoms of Asperger’s Disorder are less apparent, noticed at the earliest in preschool. More often, however, it is not until mid-elementary school years that children with Asperger’s Disorder are diagnosed. Estimates are 10 percent of those with Asperger’s Disorder receive their diagnosis at age four, 50 percent between ages five and ten, 20 percent between ages ten and twelve, and the remaining 20 percent after the onset of adolescence.
Many researchers and mental health professionals hold the view that Asperger’s Disorder and autism are two distinct disorders. Currently, the more widely held view is that Asperger’s Disorder is probably a high-functioning form of autism. The trend is to view both disorders as being on a continuum from very low-functioning to very high-functioning. This continuum is referred to as Autism Spectrum Disorders or ASD.
Those on the low end of the spectrum are diagnosed with Autistic Disorder due to their very severe symptoms; they function quite poorly in most areas of life and many fail to achieve independent adult functioning. Those on the high end of the spectrum are considered to have Asperger’s Disorder with mild symptoms; they function relatively well with an eventual outcome of independence in adulthood.
The difference between Autistic Disorder and Asperger’s Disorder is quite clear and easy for even nonprofessionals to see. The difficulty comes in distinguishing between very high-functioning autism (HFA) and Asperger’s Disorder.