Discussion

Asperger syndrome can be misdiagnosed as a variety of conditions (Box 6) requiring contradictory treatments and having a range of outcomes. Misdiagnosis as schizophrenia leads to the prescribing of neuroleptics and an unnecessary risk of tardive dyskinesia; misdiagnosis as ADHD to the prescription of psychostimulants (e.g. methylphenidate), which can cause deterioration in behaviour in this population. The condition may also be at the root of treatment-resistant mental illness in adult psychiatry. Diagnostic confusion increases individual and family burden and causes families to seek unhelpful therapies or join the wrong support groups. Neuropsychiatric disorders may share similar symptoms, for example autistic behaviour in schizophrenia or hyperactivity in ADHD. The problems this poses clinicians are compounded by partial diagnostic assessments or the use of outdated diagnostic categorisations (e.g. putting all ‘autistic-type behaviours’ into a psychotic category or being unaware of the existence of Asperger syndrome, which is not included in ICD–9 or DSM–III).

Clearly, the differentiation of Asperger disorder from other conditions is complex because of the many possibilities for misdiagnosis. The key to correct diagnosis is a precise early developmental history, with a systematic discussion of all the criteria set out for Asperger syndrome (Wing, 1981; Gillberg, 1991) or Asperger disorder (American Psychiatric Association, 1994). Assessment instruments such as the ADI–R may be useful in establishing diagnosis. A multi-disciplinary team approach is critical, and diagnosis from a solely neurological, speech and language or educational point of view must cease if families are to be spared confused partial diagnoses. Although higher-functioning autistic spectrum disorders and Asperger syndrome may describe the same population, the latter term remains useful. As applied to higher-functioning children it is more acceptable to parents and ensures appropriate service provision for a group who, despite relatively normal cognitive ability, may have comprehensive difficulties.

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Michael Fitzgerald and Aiden Corvin

Michael Fitzgerald is Henry Marsh Professor of Child Psychiatry at Trinity College Dublin (Child and Family Centre, Ballyfermot Road, Ballyfermot, Dublin 10, Ireland. Tel: +353 1 626 7512; fax: +353 1 454 4418; e-mail: .(JavaScript must be enabled to view this email address)). His primary research interests are autism and autistic spectrum disorders. Aiden Corvin is a Wellcome Trust Research Fellow in Mental Health at the Department of Psychiatry at Trinity Centre for Health Sciences, St. James’s Hospital, Dublin. Dr Corvin was formerly a registrar in child psychiatry at the Child and Family Centre, Ballyfermot. His research interests include autism spectrum disorders and psychiatric genetics, particularly of psychotic disorders.