Tuesday, April 3, 2012

Autism and Diagnostic Rates

Yes, the media are covering the news that autism rates are skyrocketing, often failing to distinguish the rates of diagnoses from the rates of incidence. Quite simply, we have no idea if "autism(s)" are increasing or not and we have a great deal of evidence that diagnostic practices are uneven, at best.

You can read some of the stories at:
http://www.cnn.com/2012/03/29/health/autism/index.html
http://www.nytimes.com/2012/03/30/health/rate-of-autism-diagnoses-has-climbed-study-finds.html

Notice this from the New York Times:
C.D.C. researchers did not meet any of the children they judged to have an autism spectrum disorder. The team made the decisions based on evaluations of the children, drawn from 14 states. The estimated rates in those states varied widely, from one in 210 children in Alabama to one in 47 in Utah.

Now, either Utah has something dangerous in their water and Alabama is the safest state in the nation, or there is something else at play. What else? It turns out that if you overlay parent income, education, and access to health care over a map of the diagnostic rates, you find that there are correlations between diagnoses and these other variables.

In 2000, the CDC found a autism diagnostic rate of 1:150. Today, that rate is 1:88, but is that an increase in autism or an increase in diagnostic awareness?

Years ago there was a study that found locations near a freeway also predicted higher diagnostic rates of autism. But, guess what? People in urban areas are more likely to be diagnosed with ASDs and those urban areas are more likely to have freeways and highways crisscrossing the metropolitan maps.

See the freeway story at:
http://articles.latimes.com/2010/dec/16/health/la-he-autism-20101217

For a time in the 1990s, Asperger's Syndrome was called the "Silicone Valley Disorder" by reporters. Why? Because children in the San Francisco Bay area were among the most likely to be diagnosed with an ASD — and any learning disability, too. There were studies that then suggested educated parents are more likely to have an autistic child. Really? Or is that these parents have university and private health clinics within minutes of their homes? And these parents can afford expensive screening exams.

Wired magazine asked: "Autism - and its milder cousin Asperger's syndrome - is surging among the children of Silicon Valley. Are math-and-tech genes to blame?"
http://www.wired.com/wired/archive/9.12/aspergers_pr.html

We have no solid evidence, only anecdotal evidence, to suggest that "autism" is actually increasing. But, remember that in 1970 or even 1980 "autism" meant the classic autism associated with severe intellectual and emotional impairment. Autism did not include the "spectrum" many people embrace today. As we widen our classification of autism, we find more autistics!

It is no accident that Utah also has the most diagnosed autistics with average and above-average IQ scores, while Alabama residents with autism diagnoses are more likely to have comorbid mental impairments. In other words, the diagnostic approach in Utah is more likely to include "high-functioning" forms of autism than the diagnostic approach of clinicians in Alabama. This might reflect social differences or training differences.

Some states, notably those with citizens of lower average incomes and educational attainments, have fewer autism cases. This does not mean there is less autism in Alabama or Mississippi than in California and Minnesota. It means California and Minnesota, with the research institutes and medical clinics, are better equipped to identify and offer services to autistics.

Several years ago the National Health System of the United Kingdom did a study of adults and found that when they screened for autism, suddenly there was a 1:100 diagnostic rate. All those adults were not autistic as children, at least not officially. These people did not suddenly develop autism, though, either. What happened was the criteria evolved and our diagnostic methods improved. It turns out, autistics have always been with us, but have been hidden. Apparently, they still are hidden in Alabama, for example.

Information about the NHS study can be read at:
http://www.dailymail.co.uk/health/article-1215283/Major-study-finds-100-adults-autism-far-common-men.html

Depending on how the DSM-V is employed in the years ahead, there might be more or fewer diagnoses of autism in the United States. The actual humans will not have changed: the criteria and methods for evaluation will have been altered.

Maybe there are more incidents of some autisms. When we group so many things under the same category, it is difficult to know what is and is not increasing. I believe many of the autisms we currently cannot identify using physical markers will be identified in my lifetime. Those will cease to be "autism" and be recategorized with new medical names. Again, the people will not have changed, but technology will have altered perceptions of what is and is not autism.

What studies like the new CDC analysis demonstrate is that there is a long, long way to go in understanding and defining autism.
http://www.cdc.gov/ncbddd/autism/data.html

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