Atypical Autism Symptoms: ICD Diagnostic Critera for Atypical Autism

The formal diagnosis of atypical autism rests on these symptoms, which can be evaluated by psychiatrists and other mental health professionals. Also see the separate page on ICD criteria for Childhood Autism.

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. (Since the WHO updates the overall ICD on a regular basis, individual classifications within it may or may not change from year to year; therefore, you should always check directly with the WHO to be sure of obtaining the latest revision for any particular individual classification.)

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

All clinical material on this site is peer reviewed by one or more qualified mental health professionals. This specific article was originally published by on and was last reviewed or updated by Dr Greg Mulhauser, Managing Editor on .

Our material is not intended as a substitute for direct consultation with a qualified mental health professional. Please seek professional advice if you are experiencing any mental health concern.

Copyright © 2002-2021. All Rights Reserved.