Autism Spectrum Disorder (ASD) diagnoses have been increasing in both the overall numbers as well as the percentage of individuals with the condition. The maps below for the US reflect this increase. Much debate has been generated over the cause of the increase -- whether it is due to changes in diagnostic criteria, environmental factors, Thimerisol or other components in vaccines, age of mother/father, "assortive mating" (more children being born to parents that are both highly analytical), fever during pregnancy, etc.
I am the father of an autistic son and have been working on mapping the data presented on this website for the past year. One trend that is apparent is that as the number of ASD diagnoses is increasing, the number of somewhat related diagnoses (Specific Learning Disabilties, Mental Retardation, etc.) is decreasing -- at least in the vast majority of states. The term for this is -- "Diagnostic Substitution". After looking at autism and other disability data reported to the Dept. of Education as required by the Individuals with Disabilities Education Act (IDEA), I believe that diagnostic substitution, is in fact, the reason for much of the increase in autism diagnoses, at least during the time that I examined the data.
I believe this is important to know for a simple reason... so that resources for both understanding autism and helping those individuals with autism that need help can be appropriately used. The idea of "diagnostic substitution" is a middle ground that between two viewpoints at opposite extremes in explaining the rise in autism diagnoses. At one extreme is the belief that the rise has to be due to environmental factors because genetics do not change at a rate fast enough to account for the increase. "Diagnostic Substitution" and the IDEA data do not rule out the possibility of a relatively small true increase in the incidence of autism; and there may be an environmental component. But if diagnostic substitution explains the majority of the autism increase, that would be consistent with the theory of autism being primarily genetic, with perhaps an environmental trigger. This is very different from there being an environmental cause (such as MMR vaccines) that has been introduced or used differently in recent years that has led to a sudden 4X increase in autism.
Equally important is that diagnostic substitution would negate the argument on the opposite extreme -- that autism is just a fad diagnosis and that the majority of people now being diagnosed are really just a little quirky and it is a waste of taxpayer money to provide services for them. Here is one example -- Autism-Welfare Nexus. What diagnostic substitution means is that the kids now being diagnosed with autism, would -- a decade or 15 years ago, have been diagnosed with conditions such as Mental Retardation, Emotional Disturbance or Specific Learning Disability. That means that services would have been provided for those children; they would have had a different "label" when receiving those services but they still would have been receiving services. This again is very different from the view that these "autistic" kids are just a little shy or anti-social and that they and their parents are unfairly abusing the educational system and taxpayers.
The maps and data on this page only show autism data and rates. It is difficult to show the decrease in other disabilities for the nation as a whole because of the variability by state. In some states the decline in other disabilities is primarily in the Specific Learning Disorder category, in others Mental Retardation, in others there is a decline in both with some also having declines in Emotional Disturbance and Speech/Language Disorder. For this reason, I have mapped out the data for each state that shows the rise in autism in contrast to another disability with the greatest decline in that particular state. Please click on the state links at the top of this page to see the data for the individual states.
One state that is very different from all the rest is Iowa. Iowa is the one state that did not have a significantly higher autism rate in 2010 compared to 2000. It is very interesting to look at the Iowa data -- please do so if you have time.
The animated map above shows the increase in the ratio of diagnosed ASD cases from 2000 through 2010.
Click on any state in the map below to see ASD ratio statistics from 2000 thru 2010 for that state.
From 1999 through 2010 US Autism Spectrum Disorder Cases increased from 65,607 to 416,680 (ages 3 through 21)
Source: US Dept. of Education IDEA data (www.ideadata.org)
The points in the map above each represent 100 ASD Diagnoses. The data is collected by state; each point is randomly placed within the state and the points do not represent true locations or clusters within any given state.
The maps on this website have been created through the use of OpenSource Software including Geoserver, Openlayers, PostgreSQL, PostGIS, ApacheTomcat, Linux (ubuntu). Many thanks to all that have contributed to Open Source Software.