ABSTRACT
The term ‘autistic spectrum disorders’ (ASD) covers pervasive developmental disorders that share common symptoms, including autism and Asperger’s syndrome. Both international classification systems – the DSM-IV-TR (APA, 2000) and ICD 10 (WHO, 1992; 1996) – have features by which autism and Asperger’s syndrome may be recognized, referring to areas of development rather than specific behaviours. Behaviours themselves vary across individuals and within an individual over time and all the behaviours may be seen in children with a range of other disorders or none. ‘Missing’ behaviours are more indicative of ASD, given the child’s general level of development, but there may be other reasons for those gaps. There may be sensory problems, for example, or extreme deprivation and abuse. Diagnostic tests are reliable, but only if used and interpreted by trained professionals. The bases of both diagnostic systems are differences in three areas of development known as the ‘triad of impairments’. These can be characterized as difficulties in:
• Emotional and social understanding • All aspects of communication • Flexibility in thinking and behaviour.
