Recent much publicised attention to autism and its putative relation to the measles, mumps, and rubella (MMR) vaccination reminds us that autism affects approximately 4 in 10 000 of the population. It is characterised by impairments in reciprocal social interaction and communication, restricted and stereotyped patterns of interests and activities, and the presence of developmental abnormalities by 3 years of age. Much of the psychiatric literature appears to overlook the organic basis,¹ with subtle neurological signs evident in many examples: learning difficulties, a high incidence of epilepsy, viral infections, tuberous sclerosis, and fragile X syndrome are known associations.

Leo Kanner, a psychiatrist at Johns Hopkins, recognised children sent to his clinic with similar characteristics, which he named “early infantile autism”. In his original description, Kanner² noted that in most cases the child’s behaviour was abnormal from early infancy. He therefore suggested an inborn, presumably genetic, defect. Subsequently, an increased concordance rate in monozygotic v dizygotic twins and a 75-fold increased risk to siblings of idiopathic cases were shown.

“Autistic psychopathy in childhood” by Hans Asperger³ was published in 1944 in German (translated into English in 1991). His description of autistic psychopathy in four cases is similar to Kanner’s “early infantile autism”⁴ Symptoms described by Asperger included the DSM-IV’s three diagnostic criteria for autism.

A Viennese physician, Asperger, described young boys of normal intelligence and language development, but who also exhibited autistic like behaviours and marked deficiencies in social and communication skills.

While Kanner reported that 3 of his 11 patients did not speak at all, and the remainder rarely used language, Asperger noted that his patients spoke “like little adults”; Kanner reported poor motor coordination but good fine motor skills, although Asperger observed that both were affected. He described:

“Impairment in social interaction, impairments in communication, and restricted, repetitive, and stereotyped patterns of behaviour, interests, and activities…”

Asperger’s cases had:

“Special interests, abnormal fixations, stereotypic play and movements, such as rocking, and ritualized behaviours.”

He described the characteristics of 11 children and he selected features crucial for diagnosis:

• a profound lack of affective (emotional) contact with other people

• intense insistence on sameness in their routines

• muteness or abnormality of speech

• fascination with manipulating objects

• high levels of visuospatial skills or rote memory but major learning difficulties in other areas

• an attractive, alert, intelligent appearance.

Most accounts include associated features, for example unusual sensory responses. Intelligence, according to Asperger’s description, encompassed all levels of intelligence from “the highly original genius…to…mentally retarded individual”. His publication received little attention outside Germany and was undoubtedly eclipsed by Kanner’s description.⁵

In England, Lorna Wing⁵ was the first to use the term Asperger’s syndrome, in 1981.⁶ Her description differed in some ways from Asperger’s. She suggested that the term be used for:

“Children and adults who have autistic features, but who talk grammatically and who are not socially aloof.”

It is likely that Kanner’s and Asperger’s syndromes are different ends of the same spectrum, with no aetiological differences. Social impairment and restricted and repetitive behaviour and interests are required DSM-IV symptoms for both autistic disorder and Asperger’s disorder; but, communication impairment signifies a diagnosis of autism, not Asperger’s disorder.