title: A qualitative analysis of lay beliefs about the aetiology and prevalence of autistic spectrum disorders.
abstract: BACKGROUND
  There has been a dramatic increase in the prevalence of autistic spectrum disorders (ASD) in the last 20 years. The reasons for this are disputed. The consensus among epidemiologists and other experts is that greater case load is due to changes in diagnostic practice rather than reflecting changing aetiological factors leading to a true increase in incidence. We set out to examine lay views concerning the aetiology and prevalence of ASD and whether they conflict with or support this consensus position.
  
  
  METHODS
  Over 100 unsolicited communications (letters e-mail and several telephone calls) were received by a UK epidemiological study of ASD. We carried out a qualitative analysis of all correspondence in order to examine spontaneously expressed lay beliefs about the prevalence and aetiology of ASD.
  
  
  RESULTS
  The majority of correspondents suggested theories about environmental causes of ASD. This study demonstrates the strength of lay belief that the true incidence of autism is rising, and this is due to risks from modern technologies and changing lifestyles.
  
  
  CONCLUSIONS
  This study based on unsolicited data highlights the contrast between lay explanations of increasing prevalence and the consensus opinion of medical experts. It also demonstrates how many people in direct contact with ASD have important information to share.
authors.affiliation: ESRC Centre for Genomics in Society, University of Exeter, Exeter, UK. g.russell@ex.ac.uk
authors.forename: G
authors.initials: G
authors.lastname: Russell
authors.forename: S
authors.initials: S
authors.lastname: Kelly
authors.forename: J
authors.initials: J
authors.lastname: Golding
mesh_terms: D002648:Child; D002659:Child Development Disorders, Pervasive / Q000209:etiology; D016021:Epidemiologic Studies; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D015995:Prevalence; D036301:Qualitative Research; D012307:Risk Factors