title: Autism spectrum disorders--are they really epidemic?
abstract: OBJECTIVE
  The aim of this paper is to report on how different external methodological factors influence estimates of ASD prevalence.
  
  
  METHODS
  PubMed searches was conducted using the search terms, "Autism", "Autistic Disorder", "Autism Spectrum Disorders", "Asperger", "Prevalence" and "epidemiology", in combination. In total 49 studies were included. We also performed a manual search for and reviewed related articles referenced in the original articles.
  
  
  RESULTS
  The reported prevalence rates of ASD vary widely, and so do the methodology used in the studies.
  
  
  CONCLUSIONS
  There are reasons to argue that the methods used in some studies cause the high prevalence rates reported recently.
authors.affiliation: Department of Habilitation, Innlandet Hospital Trust, Maihaugveien 4, 2609 Lillehammer, Norway. jorn.isaksen@sykehuset-innlandet.no
authors.forename: Jørn
authors.initials: J
authors.lastname: Isaksen
authors.forename: Trond H
authors.initials: TH
authors.lastname: Diseth
authors.forename: Synnve
authors.initials: S
authors.lastname: Schjølberg
authors.forename: Ola H
authors.initials: OH
authors.lastname: Skjeldal
mesh_terms: D002659:Child Development Disorders, Pervasive / Q000453:epidemiology*; D058872:Epidemics; D006801:Humans; D015995:Prevalence; D039781:PubMed / Q000706:statistics & numerical data