Autism spectrum disorders surprisingly common, Korean study suggests

Autism spectrum disorder may be going under-diagnosed in U.S., study suggests.

(CBS/AP) How many kids have an autism spectrum disorder? U.S. estimates have suggested a rate of about one in 100 children, but a new study from South Korea puts the number at a surprisingly high one in 38.

The scientists behind the new study don't think South Korea has more autistic children than the U.S., but instead that autism often goes undiagnosed in many nations. U.S. estimates are based on education and medical records, not the more time-consuming survey conducted in South Korea.

Two-thirds of the kids with autism traits in the study were in the mainstream school population, hadn't been diagnosed before and weren't getting special services. Many of those undiagnosed children likely have mild social impairments, rather than more severe autism.

"I'm sure some of these children probably could benefit from intervention, but I don't think we could make a statement that all would benefit from intervention," said Dr. Marshalyn Yeargin-Allsopp, chief of the Centers for Disease Control and Prevention's developmental disabilities branch.

The CDC wasn't involved in the new study, although another federal agency, the National Institute of Mental Health, provided some funding. The group Autism Speaks, which advocates for more aggressive autism screening, also helped pay for the study. Autism Speaks had no role in the study's design.

The study, published Monday in the American Journal of Psychiatry, attempted to screen all 55,000 schoolchildren, ages 7 to 12, in a district of Goyang City, near Seoul. But only about two-thirds of mainstream children participated. About 63 percent of their parents filled out a survey. The researchers acknowledged that parents of affected children might be more likely to fill out the survey.

The questionnaire used is a recognized screening tool for high-functioning autism such as Asperger's syndrome. It asks such questions as whether the child "stands out as different" in a number of ways, including lacking empathy, lacking best friends and being bullied by other children.

The study took five years to complete. The U.S. government's approach is quicker and allows more ongoing results, Yeargin-Allsopp said.

"Community providers, researchers and others are interested in prevalence of autism on a frequent basis," Yeargin-Allsopp said. "This is not possible if you're doing a screening of an entire population" as was attempted by the South Korean researchers.

The National Institute of Child Health & Human Development has more on autism spectrum disorders.