title: Two-year outcome of preschool children with autism or Asperger's syndrome.
abstract: OBJECTIVE
  DSM-IV specifies that Asperger's disorder is a type of pervasive developmental disorder without clinically significant cognitive or language delay. There are no data, however, on the outcome of children with Asperger's disorder or on whether their outcome differs from that of children with autism. The objectives of this study were to compare the outcome of groups of children with these disorders over a period of 2 years on variables independent of the defining criteria and to identify variables that might account for these differences.
  
  
  METHODS
  All children 4-6 years of age who came for assessment or were currently in treatment at a pervasive developmental disorder service of one of several centers in a large geographic region were identified. Children who received a diagnosis of autism (N=46) or Asperger's syndrome (N=20) on the basis of a diagnostic interview and had an IQ in the nonretarded range were given a battery of cognitive, language, and behavioral tests. Families were contacted roughly 2 years after the date of their enrollment in the study, and many of the tests were readministered.
  
  
  RESULTS
  Children with Asperger's syndrome had better social skills and fewer autistic symptoms 2 years after study enrollment than the children with autism. The differences in outcome could not be explained by initial differences in IQ and language abilities. Children with autism who had developed verbal fluency at follow-up were very similar to the children with Asperger's syndrome at study enrollment.
  
  
  CONCLUSIONS
  Although the exact mechanism for the differences in outcome remain to be determined, it appears that Asperger's disorder and autism represent parallel but potentially overlapping developmental trajectories.
authors.affiliation: Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada. szatmar@mcmaster.ca
authors.forename: P
authors.initials: P
authors.lastname: Szatmari
authors.forename: S E
authors.initials: SE
authors.lastname: Bryson
authors.forename: D L
authors.initials: DL
authors.lastname: Streiner
authors.forename: F
authors.initials: F
authors.lastname: Wilson
authors.forename: L
authors.initials: L
authors.lastname: Archer
authors.forename: C
authors.initials: C
authors.lastname: Ryerse
mesh_terms: D020817:Asperger Syndrome / Q000175:diagnosis* / Q000523:psychology; D001321:Autistic Disorder / Q000175:diagnosis* / Q000523:psychology; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007361:Intelligence Tests / Q000706:statistics & numerical data; D007804:Language Development; D007807:Language Tests / Q000706:statistics & numerical data; D008297:Male; D017063:Outcome Assessment, Health Care; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011581:Psychological Tests / Q000706:statistics & numerical data; D012720:Severity of Illness Index; D012951:Socialization