Lorna Wing, M.D., FRCPsych, a founding member of the National Autistic Society, consultant psychiatrist at the NAS’s Centre for Social and Communication Disorders, and author of The Autistic Spectrum, describes these areas of impairment:
Impairment of social relationships: An individual may not use or understand nonverbal behavior or develop peer relationships that are appropriate to his developmental level, or may appear aloof and indifferent to other people. Impairment of social communication: There may be a total lack of or delay in the development of speech (with no attempts to communicate by gestures). The individual does not sustain or initiate conversation, or uses language in a stereotyped and repetitive manner. Impairment of imaginative thought: An individual may have an all-encompassing, intense preoccupation with one interest or topic; or have inflexible, nonfunctional rituals or routines. Repetitive motor mannerisms such as hand flapping or spinning of objects may be observed. Often there is a lack of make-believe or social imitative play.
Difficulties in one or more of the areas listed above are required for a diagnosis of an ASD, but several additional observable behaviors do not necessarily fit into any of the three. Although on their own they do not call for a diagnosis of an ASD, these other characteristics are often associated with ASDs, and they are important when evaluating and assessing for the purpose of putting together a treatment plan.
