Reproduced, with thanks, from CAIRN: Canadian Research Agenda in Early Autism Intervention

Autistic Disorder

1. A total of six (or more) items from (1), (2), and (3), with at least two from (1), and one each from (2) and (3):
   1. qualitative impairment in social interaction, as manifested by at least two of the following:
      • marked impairment in the use of multiple nonverbal behaviours such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction
      • failure to develop peer relationships appropriate to develop mental level
      • a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest)
      • lack of social or emotional reciprocity
   2. qualitative impairments in communication as manifested by at least one of the following:
      • delay in, or total lack of, the development of spoken language (not accompanied by an attempt to compensate through alternative modes of communication such as gesture or mime)
      • in individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others
      • stereotyped arid repetitive use of language or idiosyncratic language
      • lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level
   3. restricted repetitive and stereotyped patterns of behaviour, interests, and activities, as manifested by at least one of the following:
      • encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focu
      • apparently inflexible adherence to specific, non-functional routines or rituals
      • stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements)
      • persistent preoccupation with parts of objects
2. Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years.
   1. social interaction
   2. language as used in social communication
   3. symbolic or imaginative play
3. The disturbance is not better accounted for by Rett's Disorder or Childhood Disintegrative Disorder