The estimates of children with autism spectrum disorder (ASD) in the U.S. have continued to rise significantly, according to the Center for Disease Control. As of March 2013, the CDC estimates that one in every 50 school children are diagnosed with ASD—a 1.16% increase from the estimates revealed in 20121. Other post-industrial counties are experiencing a similar trend of rising ASD incidence rates—the UK reported in 2012 an increase of 56% of children with autism in the last five years2. While ASD is increasing globally overall, however, many developing countries are reporting significantly lower rates. In China, for example, it is estimated that 1.1 in every 1,000 children are diagnosed with autism3. Similarly low rates among other developing countries are causing many to question what exactly is responsible for the difference in rates of ASD among developed and developing countries.
The most common answer to the difference in global prevalence rates is that there is better detection among developed countries. In post-industrial countries, doctors are more familiar with diagnosing autism, health services are increasingly being offered for children with ASD, and communities are often more aware of the disorder. These factors, among others, make detecting ASD in developed countries much easier than in developing countries. For example, in South East Asia, there is one psychiatrist per 100,000 people, making mental health services or diagnoses extremely difficult to access3.
Cross-cultural differences also play a large role, especially when considering the diagnosis of mental health disorders. In South Korea, the stigma of autism is so intense that many families of children with developmental delays will intentionally avoid diagnosis of ASD. In addition, as autism is diagnosed behaviorally, cross-cultural norms of behavior may interfere. For example, although difficulty speaking and lack of eye contact are early signs of ASD, cultural norms such as discouraging eye contact in parts of East Asia and an Indian belief that “male child speaks later,” makes it difficult to attribute symptoms to the disorder. Stigma and cultural norms, along with poor diagnosis or medical infrastructure, could be undermining prevalence rates, masking the amount of children that have autism in developing countries.
However, many scientists theorize that other factors may also be responsible for the increasing rates in post-industrial countries. Some claim that about one third of ASD is due to immune dysregulation during pregnancy. That is, anything that causes an inflammatory response in the pregnant mother, such as infection or an immune disorder, may expose the fetal brain to inflammatory signals and disrupt development. For example, mothers with celiac disease have an increased chance of autism by 350 percent, while those with rheumatoid arthritis have an elevated risk of 80 percent4.
This immune dysregulation is post-industrial specific because of the way our immune system evolved. According to the “Biome Depletion Theory,” our immune system co-evolved alongside microbes and parasites, of which are lacking in urban, post-industrial societies. It is therefore our lack of parasites or microbes interacting with our immune system that is causing our immune response to overreact. This is consistent with the observation that in some developing populations, such as in Cambodia, rife with parasites and infections, the autism incidence is extremely low5. In this case, a probiotic drug that is able to control the inflammatory response in pregnant women may be able to prevent some of the onset of autism.
Ultimately, the creation of mental health infrastructure and more access to adequate resources for those diagnosed with ASD among developing countries will reveal more on the causes, and thus the treatment and prevention, of ASD. With increased mental health infrastructure, we would expect to see rates of ASD rise in developing countries, and fall in the developing world. However, with developments like this, hopefully, one day, we will be better able to treat and prevent ASD globally.
 Center for Disease Control, “Changes in Prevalence of Parent-reported Autism Spectrum Disorder in School-aged U.S. Children: 2007 to 2011-2012”, United States, 2013.
 Baron-Cohen, S., et al. “Prevalence of autism-spectrum conditions: UK school-based population study,” Br J Psychiatry 195 (2009): 500-9.
 Saraceno, B and Saxena, S., “Mental health resources in the world: results from Project Atlas of the WHO,” World Psychiatry 1 (2002): 40-44.
 Velasquez-Manoff, M., “An Immune Disorder at the Root of Autism,” The New York Times, August 25, 2012, Accessed March 15, 2013, http://www.nytimes.com/2012/08/26/opinion/sunday/immune-disorders-and-autism.html?pagewanted=all&_r=0.
 Parker, W., “Helminthic Therapy: Reconstituting the depleted biome to prevent immune disorders,” The Environmental Illness Resource, Accessed March 15, 2013, http://www.ei-resource.org/articles/candida-and-gut-dysbiosis-articles/helminthic-therapy:-reconstituting-the-depleted-biome-to-prevent-immune-disorders/.