Autism and related disorders in Britain may be twice as widespread as previously thought, according to research published on Friday.
The study showed that 116 in every 10,000 children suffer from autism or autism spectrum disorders (ASD). The previous estimate was 44 per 10,000. "Prevalence of autism and related ASD is substantially higher than previously recognised," said Professor Gillian Baird, of Guy's and St Thomas' Hospital in London. "Whether the increase is due to better ascertainment, broadening diagnostic criteria, or increased incidence is unclear," she added.
The cause of autism, which usually develops before the age of 30 months, is unknown. In some cases it is apparent from birth. Children with the condition become withdrawn, self-absorbed, are often unable to communicate and do not follow normal patterns of development.
The condition is more prevalent among boys than girls. ASDs are developmental disorders characterised by different degrees of impairment in communication and social skills and repetitive patterns of behaviour.
The researchers calculated the new estimates by looking at cases of autism and ASDs in children aged nine and 10 in south London in 2001. They studied children with all forms of ASD and children with special educational needs.
The study published in The Lancet medical journal revealed 39 children per 10,000 had autism and 77 per 10,000 had ASD.
"Services in health, education and social care will need to recognise the needs of children with some form of ASD, who constitute one percent of the child population," Baird said in the study.