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Autism Spectrum Disorders: What to Make of the Latest Statistics?

Autism Spectrum Disorders: What to Make of the Latest Statistics?

Two recent reports, one conducted by the Health Resource and Service Administration (HRSA)1 and a second from the CDC,2 now estimate that the current prevalence of autism spectrum disorders (ASDs) in children born in the United States has risen from 1:150 to around 1:100. The HRSA report was based on a telephone survey of 78,037 parents involved in the 2007 National Survey of Children's Health.1 However, for its study, the CDC used a rigorous identification and confirmation system called the Autism and Developmental Disabilities Monitoring Network, which cross-references educational and health data in 11 states.2

Because boys are 4 times more likely than girls to be affected,2 these new data translate into a remarkable rate of ASD in boys of about 1:60. Perhaps the most intriguing information, however, is found in the HRSA report. In that report, 1412 parents stated that their child had had an ASD at some point—yet 40% of those parents said that their child no longer had an ASD. In other words, 40% of the children with ASDs had reportedly been cured or possibly been given a misdiagnosis. The remaining children were classified as still having mild ASD (494), moderate ASD (320), or severe ASD (90).1

Beneath an acknowledged increase, the debate over causes rages. The recent research on prevalence rates mirrors what many of us on the frontlines have known for several years now: more children than ever are receiving a diagnosis on the ever-widening autism spectrum. The debate about whether diagnostic substitution, earlier diagnosis, and improved access to services can fully explain the increase in autism prevalence will most likely continue for some time.3 It is also possible that factors such as epigenetics, or heritable changes in gene expression caused by mechanisms other than genetic mutation or recombination, may be playing an important role in the surge.4 Whatever the cause (or causes), trying to wrap one's head around a 1% prevalence rate and a possible 40% cure rate can make a practitioner pine for the days when autism was a rare disorder that he or she might see once or twice in an entire career.

What really matters in the debate: one child's story may shed some light. When my son Sean celebrated his second birthday in the mid-1990s, he was unable to communicate, showed no social interest in other people, ran out of the house with his hands cupped over his ears at the sound of a vacuum cleaner, had severe tantrums, and adhered to extremely rigid routines that made us feel trapped. Today, my son is a 14-year-old who is thriving in his eighth-grade special education classes. He has learned, thanks to my wife's dogged determination, to get along and adapt in this world. He is an avid trumpet player—first chair in his district—plays the drums in 2 rock bands, and recently placed second in the 100-meter and 200-meter freestyle in a USA Swimming meet (watch out Michael Phelps!).

If someone asked me to grade my son's autism, I'm really not sure what I would say. There are areas in which his symptoms are mild, but other areas in which his symptoms would be classed as severe; so maybe I would hedge and say that he has "moderately severe" autism. Therein lies the reason for the difficulty in trying to measure prevalence trends—yet, at the same time, the reason for hope—namely, that children change. Do I think there is a 40% cure rate for classic restrictive autism? Probably not. Might a child with mild or moderate symptoms of an ASD and uneven developmental progression be difficult to classify and later, as an adult, have a "disorder" that essentially was undetectable? Absolutely!

If we as health care workers can provide an early diagnosis and a medical home for children with autism and their families, then more children will become adolescents like my son, who because they feel accepted, will not care whether the rate is 1 in 1000 or 1 in 10.


1. Kogan MD, Blumberg SJ, Schieve LA, et al. Prevalence of parent-reported diagnosis of autism spectrum disorder among children in the US, 2007. Pediatrics. 2009;124:1395-1403.
2. Rice C. Prevalence of autism spectrum disorders—Autism and Developmental Disabilities Monitoring Network, United States, 2006. MMWR. 2009;58:1-20.
3. Shattuck PT. The contribution of diagnostic substitution to the growing administrative prevalence of autism in US special education. Pediatrics. 2006;117:1028-1037.
4. Gregory SG, Connelly JJ, Towers AJ, et al. Genomic and epigenetic evidence for oxytocin receptor deficiency in autism. BMC Med. 2009;7:62. http://www.biomedcentral.com/1741-7015/7/62. Accessed December 29, 2009.

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