Prevalence of autism spectrum conditions in primary schools (CAST)

Carrie Allison, Carol Brayne, Simon Baron-Cohen, Fiona Matthews, Sophia Sun

We developed the CAST, formerly known as the Childhood Asperger Screening Test but renamed as the Childhood Autism Spectrum Test. The change of name reflects that it was originally designed for a prevalence study of Asperger Syndrome in childhood but is useful for low-functioning children too. We found that the CAST discriminates cases from controls well, and that CAST scores show strong heritability in a twin study.

We used the CAST as a screening instrument in a large population study of 20,000 primary school age children in Cambridgeshire. Results confirm recent studies from other prevalence studies that autism spectrum conditions are found in about 1% of the population. This study also found for the first time that for every 3 known cases of ASC there are 2 undiagnosed cases. 

We have found associations between the CAST and foetal testosterone, and are exploring its relationship to a related screening instrument, the Autism Spectrum Quotient-Child Version. We are also now using the CAST in two new population studies, in China and in the Netherlands.


Selected References

429: S. Baron-Cohen, B. Auyeung, E. Ashwin, R. Knickmeyer (2009)
Fetal testosterone and autistic traits: A response to three fascinating commentaries
British Journal of Psychology 100:39-47

379: C. Allison, J. Williams, F. Scott, C. Stott, P. Bolton, S. Baron-Cohen and C. Brayne (2007)
The Childhood Asperger Syndrome Test (CAST): Test-retest reliability in a high scoring sample
Autism 11(2):173-185

346: A. Ronald, F. Happé, P. Bolton, L. M. Butcher, T. S. Price, S. Wheelwright, S. Baron-Cohen and R. Plomin (2006)
Genetic heterogeneity between the three components of the autism spectrum: a twin study
Journal of the American Academy of Child & Adolescent Psychiatry 45(6):691-699

188: F. Scott, S. Baron-Cohen, P. Bolton and C. Brayne (2002)
Brief Report: Prevalence of autism spectrum conditions in children aged 5-11 years in Cambridgeshire, UK
Autism 6(3):231-237

175: F. Scott, S. Baron-Cohen, P. Bolton and C. Brayne (2002)
The CAST (Childhood Asperger Syndrome Test): Preliminary development of UK screen for mainstream primary-school children
Autism 6(1):9-31

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