A diagnosis of Asperger syndrome cannot currently be made with confidence before the child's fifth birthday, and usually not until well into school age. This is partly because symptoms during the first few years may be subtle or uncharacteristic, partly because other diagnoses (including autistic disorder, ADHD and DAMP) may have been made and the ‘Asperger problems’ overlooked. The early symptoms are often sleep problems, ‘stubbornness’, passivity, attention problems, and unusual development of voice, speech and/or language.

This chapter deals with the definition of Asperger syndrome, and of other diagnostic concepts that will be repeatedly referred to in the book.

Asperger syndrome

Several years later, the International Classification of Diseases (ICD-10) published by WHO, included Asperger syndrome as a formal diagnosis for the first time (Table 2.3).

There are currently at least four definitions of Asperger syndrome that are frequently cited in the literature. Hans Asperger never published any formal diagnostic criteria. Lorna Wing, in her seminal 1981 paper, listed a number of symptoms but provided no algorithm for a final diagnosis.

The first operationalised diagnostic criteria to be presented were those of I. Carina Gillberg and Christopher Gillberg at the first International Conference on Asperger syndrome in London in 1988. These criteria were published in a scientific journal in 1989 and elaborated by Christopher Gillberg in 1991 (see Table 2.1). The six criteria are based on Asperger's descriptions of his first four published cases (Fritz, Harro, Ernst and Hellmuth from his 1944 paper).