Diagnosis and differential diagnosis of Asperger syndrome

Asperger syndrome is an uncommon condition, but probably more common than classic autism (the only published population study estimated prevalence at 36 per 10 000 children for Asperger syndrome and 5 per 10 000 for autism (Ehlers & Gillberg, 1993)). Misdiagnosis or delayed diagnosis of this disorder is a serious problem, and the average age at diagnosis is several years later than for autism (Gillberg, 1989). Obviously, this can be traumatic for individuals and families; furthermore, the most effective intervention programmes begin early, and establishing management strategies at an early age can minimise later behavioural problems (Howlin, 1998).