Atypical Autism Diagnostic Criteria

Please see our separate note on Treatment, Mental Disorders and Basic Science for important caveats on the role and definition of diagnostic criteria.

ICD-10 Criteria for Atypical Autism

The following information is reproduced verbatim from the ICD-10 Classification of Mental and Behavioural Disorders, World Health Organization, Geneva, 1992.

F84.1 Atypical Autism

A pervasive developmental disorder that differs from autism in terms either of age of onset or of failure to fulfil all three sets of diagnostic criteria. Thus, abnormal and/or impaired development becomes manifest for the first time only after age 3 years; and/or there are insufficient demonstrable abnormalities in one or two of the three areas of psychopathology required for the diagnosis of autism (namely, reciprocal social interactions, communication, and restrictive, stereotyped, repetitive behaviour) in spite of characteristic abnormalities in the other area(s). Atypical autism arises most often in profoundly retarded individuals whose very low level of functioning provides little scope for exhibition of the specific deviant behaviours required for the diagnosis of autism; it also occurs in individuals with a severe specific developmental disorder of receptive language. Atypical autism thus constitutes a meaningfully separate condition from autism.

Includes:

• atypical childhood psychosis
• mental retardation with autistic features