Is your child autistic? The question strikes fear into the hearts of parents but scientists have now developed a screening test for autism which they say could detect the condition.
The 12-point questionnaire was more than 90 per cent accurate in identifying children who had been independently diagnosed with autism and could help identify other children with "functional impairment," researchers said.
The test could also be used to detect the condition in dysfunctional professors, train-spotters and others with eccentric habits who are popularly thought to share autistic traits.
In a trial run of the test at Great Ormond Street Hospital in London, the mothers of more than 400 children, half of whom were autistic, filled in the questionnaire, which has a maximum score of 24. The autistic children on average scored 16 to 17, compared with two to three for other children.
A third group of children, referred to the hospital's clinic for social and communication disorders but not diagnosed as autistic, scored between 11 and 12.
The questionnaire was developed by Professor David Skuse and colleagues at the Institute of Child Health, London, and the findings are published in the British Journal of Psychiatry. Professor Skuse said there was disagreement among scientists about whether autism was a distinct abnormal condition or one end of the normal spectrum of behaviour. The test could help settle that dispute.
Between 60 and 100 children in 10,000 are thought to have autistic spectrum disorder, of whom 20 to 25 are diagnosed with classical autism. The condition normally develops in children before the age of two and leads to severe difficulties in communicating and forming relationships.
Professor Skuse said: "Autism probably isn't a separate condition. It is probably on a continuum with normal behaviour. The boundaries are not distinct - it is not a precipice but a gentle slope. If you have enough of these symptoms [identified on the questionnaire] you are likely to have social and educational difficulties that could affect your ability to fit in. You can't draw a line and say people with a score above have autism because it will depend on other factors. But, the higher your score, the more likely you are to have functional impairment."
Traits seen in autism were also seen in other conditions, lending support to the theory that the condition is on a continuum with normal behaviour.
"A lot of kids with conduct disorder who appear to be just naughty also have problems with language, leaping from subject to subject. We are increasingly recognising that these symptoms are not confined to autism," Professor Skuse said.
Current methods of identifying children with autism depend on GPs or health visitors recognising signs of the disorder and referring children for assessment. But many parents believe the condition is under-diagnosed as the assessment is expensive and too few children are referred.
"If this screening test were applied across a community of school-age children, we could get a sense of how many had autistic traits. The checklist could be used to establish its prevalence in the population," Professor Skuse said. The incidence of autism in Britain has been rising for more than a decade.