The Rise In Autism Explained

According to a new research, the rise in autism in special education students is not down to our environmental factors like pesticides in our food or even vaccines, it is down to the changing of diagnostic criteria. There has been an increase of 300% in cases diagnosing autism over the period of 2000 up to 2010 in the US. So what exactly has caused this increase in autism cases? An increased understanding or awareness of the learning disability and just a broadening scope of symptoms associated with autism is now understood to be a very large contributor to this increase. That is it, it has all been down to a reclassification of the condition itself.

Autism is a tricky disorder to pin down as it over laps with a lot of other disorders that are on the same spectrum, such as Angelman Syndrome, Fragile X Syndrome and Aspergers Syndrome to name but a few. They managed to pin down the cause of the increase in autism cases by first noting that there was no significant increase in children enrolling in special needs education. While there was no increase in numbers with learning disabilities they did notice a corresponding decline in students diagnosed with other learning disabilities. Students that would have normally been diagnosed in previous years with some of the other disorders that were previously mentioned were being diagnosed with autism.

A chart illustrating the increase in autism and the decline in other intellectual disabilities
A chart illustrating the increase in autism and the decline in other intellectual disabilities

The reason autism is hard to define is because of it’s overlapping of other conditions. Psychologists have always tried to classify conditions with their main symptoms and manifesting features that can be observed in a clinical setting. However with autism, any particular individual may exhibit more or less symptoms than another person with autism and depending on the manifesting symptoms, two individuals with autism may not share any common symptoms at all. Santhosh Girirajan, assistant professor at Penn State and head of the research team went on to say:

“The tricky part is how to deal with individuals who have multiple diagnoses because, the set of features that define autism is commonly found in individuals with other cognitive or neurological deficits.”

The age of the person during reclassification has also played a fairly significant role in the likely hood of someone being diagnosed with autism rather than another disability. 59% of autism cases for 8 year olds is due to reclassification and at the age of 15 years old the percentage is as high as 97%. This results in other previously diagnosed conditions becoming less prevalent as a broader classification of autism is applied to the diagnostic criteria. Prof. Girirajan also went on to say:

“The high rate of co-occurrence of other intellectual disabilities with autism, which leads to diagnostic reclassification, is likely due to shared genetic factors in many neurodevelopmental disorders,”

“When individuals carrying classically defined genetic syndromes were evaluated for features of autism, a high frequency of autism was observed, even among disorders not previously associated with autism, suggesting that the tools for diagnosing autism lose specificity when applied to individuals severely affected by other genetic syndromes.”

So there has not been any drastic increase in people requiring special needs education or an increase in people with learning disabilities after all. I’m sure this will reassure the anti-vaxxers that vaccines do not in fact cause autism. Or you know, maybe it won’t, it probably won’t in all honesty…

Conor John

As a graduate of Computer Science I have a very keep interest in technology and try to stay informed on as much as I can. I have also always been interested in science, mainly biology, nature and health. I hope you enjoy my articles.

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