Brief report: prevalence of autism spectrum conditions in children aged 5-11 years in Cambridgeshire, UK.

The study aimed to establish prevalence of the broader autistic spectrum, including Asperger syndrome, in 5- to 11-year-olds in Cambridgeshire, UK. Cases of diagnosed autism spectrum condition (ASC) in children who were in Cambridgeshire schools and aged between 5 and 11 years on 31 December 1999 were sought using public records, screening instruments, educational psychology and special educational needs coordinator (SENCO) records. We report a prevalence of ASC in the age group 5-11 years of almost 0.6 percent (57 in 10,000). This is 11 times higher than the rate of classic autism but in line with other recent national and international rates for the broader spectrum. In the responding mainstream schools the prevalence was 0.33 percent. In the responding special school population it was 12.5 percent. The overall sex ratio of the children with ASC replicated findings for classical autism of 4:1 (M:F), but in those children being educated in mainstream schools the sex ratio was 8:1 (M:F).