A carefully conducted study published online this week in the American Journal of Psychiatry suggests that the prevalence of autism spectrum disorders (ASDs) may be far higher than thought.
Young-Shin Kim of the Yale Child Study Center and fellow researchers in the U.S., Korea and Canada screened 55,000 elementary school students ages 7-12 in a community in South Korea and found the prevalence of ASDs among them to be about 1 in 38. That's much higher than the most recent U.S. estimate, which puts the number at about 1 in 110 children.
Why the big difference?
It's not that South Korean children are inherently more likely to have ASDs than other children, the study notes. And the researchers worked hard to control for such factors as cultural bias that might make parents reluctant to have their children identified as being autistic and for other factors that might affect the sample of students studied. They also took into account any potential differences in the way ASDs might be expressed or diagnosed in that culture.
In the end, they found it was likely the populations of children targeted for analysis in the first place that accounted for the difference. While previous studies typically looked primarily at the prevalence of ASDs among subgroups of children considered most likely to be affected (such as those already in special-education programs or those classified as children with disabilities), the study explains, this team's screenings included both those high-risk children and those in the general student body.
Two-thirds of the cases of ASDs that the screenings identified were among the general-student population, children whose disorders had not been recognized and were going untreated.
The study notes that the structure and rigors of the South Korean education system might make it easy for some students with ASD to "fly under the radar" without drawing attention to themselves or certain behaviors.
Though this study looked only at one community in South Korea, the authors note that if its more-inclusive screening method were to be applied to other populations throughout the world, the estimate as to how many children have ASDs might rise considerably.