The word “autism” has lost its specificity. With respect to children the term “autism” referred originally to a group of youngsters first described by Dr. Leo Kanner in 1943 to whom he attached the diagnosis of Early Infantile Autism. These were children who from a very early age showed “autistic” aloneness, mutism or language that failed to convey meaning to others, suspected deafness, a tendency to stare through but not at people, obsessive desire for sameness, use of the third person rather than personal pronouns, echolalia, literalness, fascination with spinning objects and rhythm, over-all serious-mindedness, phenomenal rote memory, and many repetitive and stereotypical behaviors, to name some of their characteristics and behaviors. They were children often described as being “in a world of their own.”
Over the years, however, the term “autism” has been expanded to include what now is generally referred to as Autistic Disorder. This official diagnostic category includes, but is not now limited to, Kanner’s original Early Infantile Autism group. In a state-wide survey in Wisconsin only about 25 percent of children with Autistic Disorder actually had Early Infantile Autism. The remainder had many of the same signs and symptoms of Early Infantile Autism, but with an onset either later in childhood, at about age two or three, after a period of normal growth and development, or else they presented a clinical picture of autistic symptoms mixed with signs of other organic brain dysfunction.
At the present time Autistic Disorder is a spectrum condition ranging in severity of disability from mild to profound. It is classified as a developmental disability, meaning it is in fact an organic or biological, not psychological, disorder that involves dysfunction of some portion of the central nervous system. In reality Autistic Disorder should probably more accurately be called “the Group of Autistic Disorders” because it appears those disorders stem from a variety of causes, and not from a single etiology. Also, those various disorders or sub-groups present with a variety of differing clinical symptoms and onsets, and have varying clinical courses and outcomes. No single cause has been identified for either Autistic Disorder, or the sub-group of Early Infantile Autism, but it appears that some cases are genetic or in-born, and others involve, perhaps, some environmental, nutritional, metabolic or other causes. The search for those causes is underway, as is the search for specific treatments for specific sub-groups of this over-all spectrum condition of Autistic Disorder.
Finally “autism” as a disorder needs to be separated from “autism” as a symptom. A number of CNS disorders, such as Mental Retardation or other forms of CNS injury or disease, can have “autistic” symptoms or “autistic” behaviors as a part of the overall clinical picture. But those autistic symptoms are not synonymous with, or the same as, Autistic Disorder as such.
Within the broad classification of Autistic Disorder, as pointed out above, approximately one in 10 such persons has savant syndrome at a splinter skill, talented or prodigious level, with splinter skills being by far the most common presentation. Most clinicians include Asperger’s Disorder in the spectrum of Autistic Disorders, and in individuals with Asperger’s Disorder savant skills are likewise quite common, at least at that 10 percent level. Interestingly Dr. Hans Asperger, in Austria in 1944, when he first described the disorder that now bears his name, entirely unaware of Dr. Kanner’s work in America, also applied the term “autistic” to his group of newly described patients, just as Dr. Kanner had applied that term to his group of youngsters only a year earlier in the United States.
In summary, Autistic Disorder appears in fact to be a group of disorders, one sub-group of which is Early Infantile Autism as originally described by Dr. Kanner. Onset can be from birth or symptoms can occur after a period of normal development. The etiology is organic, not psychologic, and the causes are apparently several, rather than a single one. Within Autistic Disorder as many as 10 percent of such individuals have savant syndrome. However savant syndrome can also occur in conditions other than Autistic Disorder, although not as frequently. Therefore not all autistic persons are savants, and not all savants are autistic.
Update: The May 6, 2002 issue of TIME magazine has a special section entitled “The Secrets of Autism” providing in-depth articles on the apparent “explosion” in cases of Autism and Asperger’s being reported by some observers, in the United States generally and in the Silicon Valley particularly, and provides as well some detailed recent research findings regarding the several proposed causes of those disorders. It is a very informative and comprehensive update. By way of perspective, with respect to the sudden “explosion” of Autism and Asperger’s, however, this sentence is particularly important: “While many experts believe the increase is a by-product of a recent broadening of diagnostic criteria, others are convinced that the surge is at least in part real and of grave concern.” That dispute between a real increase in cases, or an apparent increase because of broadened criteria and better case finding, continues. With respect to the many causes explored in the article, this sentence provides a crucial perspective: “In the end, it is not merely possible, but likely, that scientists will discover multiple routes—some rare, some common; some purely genetic, some not – that lead to similar end points.”
As pointed out in the FAQ answer above, Autistic Disorder is best described as a GROUP of disorders, rather than a single condition, where the final common symptom and behavioral pathways result in a shared symptom complex with multiple etiologies. It is unlikely that “Autistic Disorder” springs from a single cause, just as “Mental Retardation,” as a disorder, for example, does not spring from one cause alone. Mental Retardation, while a condition different from Autistic Disorder, does provide another example of a circumstance in which shared traits and behaviors fuse into a final common symptom path, producing an overall symptom complex which stems from a variety of different causes (e.g. Down Syndrome; phenylketonuria(PKU); perinatal hypoxia; post-natal brain trauma etc.)