Comorbidity of Down Syndrome and Autism

Robert J. Pary, M.D.
Associate Professor of Psychiatry
Southern Illinois University, School of Medicine
P.O. Box 19230
751 Rutledge Street
Springfield, IL 62794-9230
The Habilitative Mental Healthcare Newsletter
Jan/Feb 1997, Vol. 16, No. 1.
© 1997 Pysch-Media, Inc.
  Reprinted with permission of Psych-Media, Inc., publishers of Psychiatric Aspects of Mental Retardation Reviews, Habilitative Mental Healthcare Newsletter, and the journal Mental Health Aspects of Developmental Disabilities.
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Among persons with Down Syndrome, about 10% may have autism according to Howlin, Wing and Gould.1 These authors describe four boys (one was 8-years-old, one 9 years-old, and two 11-years-old). All four boys had significant abnormalities in the core criteria of autism:(a)impaired social interactions;(b)impaired communication and (c) stereotyped routines. They had impaired social interaction as evidenced by: lack of awareness of others' feelings, inability to seek comfort, impaired imitation, lack of social play, and poor peer relationships. They also had poor eye contact nonverbal communication) and impaired imagination. Three of four showed stereotyped speech. All four children showed the following stereotyped routines: motor stereotypies, preoccupation with parts of objects, distress over trivial changes,insistence on routines and preoccupation with a narrow interest.

Two of the four disliked physical contact. All four either were aggressive to peers or would push away other children. All four flapped their arms and three of the four rocked back and forth. Their special interests ranged from fitting things in boxes, specific videos, spinning things, flickering candles and switches. They were attached to such objects as leaves and sticks, a pink hair brush and a piece of hose-pipe. All four had fixed daily patterns and/or fixed places for objects.

One of the more striking points emphasized by the authors is that autism is diagnosed later in persons with Down syndrome than in the general population. Typically, autism is diagnosed before school age. In Down syndrome, the diagnosis is made much later. The authors stress that the parents the four boys had concerns about their sons' development. The parents of these children had difficulties getting professionals to consider autism as the reason why their sons were falling further behind in school. For example, the school reports did not indicate any concerns about social development. Nor did reports suggest that they were different from their peers.

The authors note the obvious effects of autism on the children's need for specialized teaching that is highly structured for the child's particular skills and deficits. They also emphasize once a diagnosis of autism is made, it can be a relief for the parents. They can be referred to parental support groups for children with autism.

Diagnosing autism in persons with Down syndrome is akin to the problem of the mental retardation overshadowing a diagnosis of mental ilness. This article suggests that the occurence of autism and Down syndrome is under-recognized. Perhaps, future studies will be able to determine whether ten percent of individuals with Down syndrome are at risk for autism.

  1. Howlin P, Wing L, Gould J. The recognition of autism in children with Down syndrome—Implications for intervention and some speculations about pathology. Dev Med Child Neurol 1995;37:404-414.
For reprints: Department of Psychology, St. George's Hospital Medical School, Tooting, London S17 ORE, U.K.