Prevalence of autism-spectrum conditions

UK school-based population study

Baron-Cohen, Simon
Scott, Fiona J.
Allison, Carrie
Williams, Joanna
Bolton, Patrick
Matthews, Fiona E.
Brayne, Carol

Simon Baron-Cohen, BA (Hons), PhD, FBPsS, MPhil (Clinical Psychology), Fiona J. Scott, BSc (Hons), PhD, C.Psychol, Carrie Allison, BA (Hons), Autism Research Centre, Department of Psychiatry, Cambridge University; Joanna Williams, BA (Hons), MPhil, PhD, Department of Public Health and Primary Care, Institute of Public Health, Cambridge University; Patrick Bolton, MA, BSc, MBBS, PhD, FRCPsych, Autism Research Centre, Department of Psychiatry, Cambridge University; Fiona E. Matthews, MRC Biostatistics Unit, Institute of Public Health, Cambridge University; Carol Brayne, MSc, MD, FRCP, FFPHM, Department of Public Health and Primary Care, Institute of Public Health, Cambridge University, UK

Correspondence: Simon Baron-Cohen, University of Cambridge, Autism Research Centre, Department of Psychiatry, Douglas House, 18b Trumpington Road, Cambridge CB2 8AH, UK. Email: [email protected]

First received 17 Sep 2008, final revision 19 Nov 2008, accepted 16 Dec 2008

^*These authors contributed equally to the work.

British Journal of Psychiatry 194(6):p 500-509, June 2009.

Background

Recent reports estimate the prevalence of autism-spectrum conditions in the UK to be 1%.

Aims

To use different methods to estimate the prevalence of autism-spectrum conditions, including previously undiagnosed cases, in Cambridgeshire.

Method

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 10000 and 99 per 10000 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 10000, including previously undiagnosed cases.

Conclusions

This study has implications for planning diagnostic, social and health services.

Declaration of interest

F.J.S acted as an expert witness for the diagnosis of autism-spectrum conditions and for the measles, mumps and rubella vaccine litigation, but not for children in the population covered by this study.