Is There a Real Increase in the Incidence of Autism?

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In November 2015, the CDC announced that, in 2014, the incidence of autism among children had increased in just one year from 1:68 to 1:45 children.

According to the Washington Post: The report from the Centers for Disease Control and Prevention and National Center for Health Statistics shows that the prevalence of autism in children ages 3 to 17 went up about 80 percent from 2011-2013 to 2014. Instead of 1 in 80 (or 1.25 percent), children having autism -- a number that has alarmed public health officials in recent years and strained state and school system resources -- researchers now estimate that the prevalence is now 1 in 45 (or 2.24 percent).

These alarming results were based on a CDC survey which had been changed over the past year. Could those changes have caused an apparent, rather than real, increase in diagnoses?  The CDC's report, entitled Estimated Prevalence of Autism and Other Developmental Disabilities Following Questionnaire Changes in the 2014 National Health Interview Survey, suggests that that might very well be the case. Not only did the survey change, but all results of the survey were based, not on medical or school records, but on parent responses -- which may not be completely accurate.

Other interesting findings from the survey included a rediscovery of the reality that most children with autism are from relatively wealthy, white, educated, married parents living in a major metropolitan area. While this study doesn't mention the fact, studies have also found that the age of parents has an impact on risk of autism.

These facts suggest a possible cultural or socioeconomic bias in reporting and/or diagnosis.

An older Danish study looking into the question concluded:Changes in reporting practices can account for most (60 percent) of the increase in the observed prevalence of ASDs in children born from 1980 through 1991 in Denmark. Hence, the study supports the argument that the apparent increase in ASDs in recent years is in large part attributable to changes in reporting practices.

But on the other hand, there is no question that more and more children do seem to have autism diagnoses. Some researchers say that the issue is not that the numbers are increasing but that more and more people are accurately diagnosing -- and the true numbers are finally being revealed. autism on the rise? And, if it is...why?

How and Why Autism Diagnoses First Exploded:

Autism was first described as a unique disorder in the 1940s. It was described by Dr. Leo Kanner, and included only those children with what might be described today as "severe" or "level 3" autism spectrum disorder.

Up until 1990, autism was not included in legislation aimed at guaranteeing an education to individuals with handicaps. In 1990, the new Individuals with Disabilities Education Act added autism to its list of categories of children and youth served under the act. The new law also added transition services and assistive technologies to its requirements. Autism had never been tracked as an educational statistic before 1990.

Since 1990, the incidence of autism in schools has risen dramatically.

In 1991, the Autism Diagnostic Interview was published. This was the first generally recognized tool for diagnosing autism.

In 1992, the American Psychiatric Association released the Diagnostic and Statistical Manual (DSM-IV), which refined diagnostic criteria for autistic disorder. Autism became a spectrum disorder; in essence, it became possible for someone to be very autistic or mildly autistic. New diagnoses, including the "high functioning" Asperger syndrome and the "catch-all" PDD-NOS, were added to the manual.

In the early 1990s, with new diagnostic tools and categories available, autism diagnoses began to soar. In the 10 years between 1993 and 2003, the number of American schoolchildren with autism diagnoses increased by over 800%. Between 2000 and 2010, the number went from 1:150 to 1:68.

Why Did Autism Diagnoses Soar?

Clearly, there are two schools of thought on this issue. On the one hand are those who say that the change in diagnostic criteria, combined with new school statistics and rising awareness of autism all created an apparent (but not real) epidemic.  This theory is almost certainly correct -- to at least some degree -- but while it may explain a large percentage of the increase it may not explain a more modest increase.

On the other hand, are those who say that some external factor has caused a real increase in the number of individuals who actually have symptoms that are diagnosable with autism.  There are many different theories as to what that external factor may be -- and (of course) it is possible to correlate the increase in autism diagnoses with an increase in many other things ranging from cell phone use to GMO's to vaccine use.  While some of these correlations seem downright silly, others have attracted serious interest from researchers.

Are Autism Diagnoses Still on the Rise?

This question is still up in the air, especially now that the definition of and criteria for diagnosing autism have changed (with the 2013 publication of the DSM-5). There are many different perspectives on what is likely to happen with the new criteria. Some experts expect a decline in autism diagnoses now that Asperger syndrome and PDD-NOS are no longer available as "catch-all" options. Others expect an increase, as awareness and services improve. The new data provide some insight -- but clearly, there are plenty of opinions on its validity and usefulness!


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