Results from a large study of autism among Korean children are making a big splash in the health news (e.g., here). Prevalence of this disorder was studied in a "total population sample" and the results published in the May 9 issue of the American Journal of Psychiatry. The study is making a splash because estimates of prevalence among Korean kids, 2.64% or more than twice as high as among American or British kids, where it's around 1%. (We are unable to access the paper online, but the Autism Science Foundation Blog cites it generously here, the source of our quotes from the paper.)
This study was conducted between 2005 and 2009 in the Ilsan district of Goyang City, South Korea, a stable, residential community near Seoul (area, 102 km2; population, 488,590) and representative of the general South Korean population (Korean Statistical Information Service, Capital Region Population, 2006). The target population (N=55,266) included all children born from 1993 through 1999 (ages 7–12 years at screening) and attending Ilsan elementary schools, as well as children in the same age group enrolled in the Ilsan Disability Registry between September 2005 and August 2006. Thirty-three of 44 elementary schools agreed to participate; 36,592 children were enrolled in participating schools and 294 in the Disability Registry...Two thirds of the cases they found were among kids in the mainstream school population, previously "undiagnosed and untreated". The authors suggest there could be cultural reasons for this (apparently autism can be a stigma that affects an entire family in Korean society). They also suggest that kids on the autism spectrum may do better in Korea's highly structured school system than they do in the US, so can be fairly successful even without diagnosis and specialized support, and thus have flown under the radar.
The authors further conclude that prevalence estimates are likely to go up in the US and the UK if their methods are followed.
But, the "autism spectrum disorder" (ASD) category is a fluid one, generally having become broader over the years as more is learned about apparently similar behavioral disorders. And, as a cynic might say, increasing the topic-pool for researchers, special ed programs, and other interests. The broadening of the definition, as well as the increased awareness of the spectrum have correlated with a rapid increase in prevalence of autism in the US over the past several decades. Thus, it has been difficult to sort out whether the increase has been largely due to changing definitions and awareness or in fact to more cases.
Therefore, the suggestion that because prevalence is higher in Korea than in the US means that prevalence has been underestimated in the US -- and that thus many children are being denied treatment and schooling that would improve their chances of success -- assumes that prevalence is real and there to be uncovered rather than at least somewhat dependent on definitions and awareness. We aren't arguing at all that the disorder doesn't exist, simply that if you throw more symptoms into the pot, you'll get more kids with what is called ASD. If behavior has a distribution, as it seems to--such as a 'normal' distribution--then it's a continuum and one can choose whatever cutoff points one wants to define a person's trait.
Not surprisingly, the intensive and very expensive search for genes 'for' ASD has yielded no genes with large effects. This is because autism is a complex trait, and like all complex traits, is more likely to be polygenic than due to single genes. The heterogeneous definition of the trait doesn't help, either. The more continuous the distribution of what's being measured, the more likely it is to be complex--that's the nature of nature.
But the suggestion in this paper that it's incumbent upon researchers to estimate the true prevalence of ASD so that affected children can get the individualized attention they deserve (which they certainly do) is troublesome. What is 'true' depends on where you draw the line, even if measurement and interpretation were perfect. Wouldn't every child benefit from individualized attention, whether or not they have been diagnosed with a disorder? The brightest kids get it, and thrive. Athletic kids get it, and musical kids, kids into mechanics or art or theatre, as well as kids with labeled disorders. But these labeled kids are the only ones with IEPs (individualized education protocols).
There are several issues here. One, the solution isn't to label more kids but to give more attention to every kid. Yes, that's asking for a fundamental remake of the public school system but rather than expand our definitions so that, say, shyness becomes social anxiety disorder, and thus druggable, and every child with any symptom along the autism spectrum becomes treatable, it would behoove us to recognize that all behaviors fall along a spectrum. And every child deserves an IEP. And two, we should not give in to the pressure to dope everyone up on maintenance meds.