title: Prevalence of autism-spectrum conditions: UK school-based population study.
abstract: BACKGROUND
  Recent reports estimate the prevalence of autism-spectrum conditions in the UK to be 1%.
  
  
  OBJECTIVE
  To use different methods to estimate the prevalence of autism-spectrum conditions, including previously undiagnosed cases, in Cambridgeshire.
  
  
  METHODS
  We carried out a survey of autism-spectrum conditions using the Special Educational Needs (SEN) register. A diagnosis survey was distributed to participating schools to be handed out to parents of all children aged 5-9 years. The mainstream primary school population was screened for unknown cases.
  
  
  RESULTS
  The prevalence estimates generated from the SEN register and diagnosis survey were 94 per 10 000 and 99 per 10 000 respectively. A total of 11 children received a research diagnosis of an autism-spectrum condition following screening and assessment. The ratio of known:unknown cases is about 3:2 (following statistical weighting procedures). Taken together, we estimate the prevalence to be 157 per 10 000, including previously undiagnosed cases.
  
  
  CONCLUSIONS
  This study has implications for planning diagnostic, social and health services.
authors.affiliation: University of Cambridge, Autism Research Centre, Department of Psychiatry, Douglas House, 18b Trumpington Road, Cambridge CB2 8AH, UK. sb205@cam.ac.uk
authors.forename: Simon
authors.initials: S
authors.lastname: Baron-Cohen
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Scott
authors.forename: Carrie
authors.initials: C
authors.lastname: Allison
authors.forename: Joanna
authors.initials: J
authors.lastname: Williams
authors.forename: Patrick
authors.initials: P
authors.lastname: Bolton
authors.forename: Fiona E
authors.initials: FE
authors.lastname: Matthews
authors.forename: Carol
authors.initials: C
authors.lastname: Brayne
mesh_terms: D001321:Autistic Disorder / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D010290:Parents; D015995:Prevalence; D011795:Surveys and Questionnaires