Monday, November 16, 2015

Why The New 1 in 45 Autism Numbers Shouldn't Surprise You

Shannon Des Roches Rosa

We've said it before, we'll say it again: There Is No Autism Epidemic. Not even after US estimates for autism prevalence recently rose to 1 in 45.

How do we know there's no autism epidemic? Two reasons:
  1. A comprehensive survey of autism prevalence in Korea estimated a rate of 1 in 39, as reported in 2011. There's no reason US rates should be much different, so the new numbers are likely portraying reality more accurately, rather than indicating reality is changing.
  2. Researchers have been saying for years that autism's prevalence has mostly risen in response to changes in diagnostic criteria, rather than due to environmental triggers or other causation ideas.
The role of changing diagnostic criteria in rising autism rates is particularly relevant right now, given that theme's prominence in Steve Silberman's award-winning, current bestseller NeuroTribes. Silberman devotes a sizable section of the book to describing how British researcher Lorna Wing helped revamp autism diagnostic criteria in the 1980s. When Dr. Wing widened those criteria to include the full spectrum of autistic experiences, she fully expected autism prevalence to rise dramatically as a reuslt. As Silberman writes in a related article at BBC Future:
"In fact, the primary contributor to the dramatic spike in autism prevalence in recent decades is the fact that a broad range of children, teenagers, and adults on the spectrum are able to get diagnosed at all. Until the 1980s, there was no “autism spectrum” as a diagnostic category."
So what lies behind the current uptick in estimated US autism prevalence? As science writer Emily Willingham reports, it has to do with a tweak in the way interviewers questioned parents about their children. That's it. Once again, there's a simple explanation, rather than a concealed smoking gun. Per Willingham:
"Not even the most die-hard causation theorist could argue that in a single year or handful of years, something environmental, like vaccines, caused a near-doubling of autism prevalence in children ages 3 to 17 years."
Autism prevalence rates will hopefully continue to rise, because -- ideally -- higher rates would indicate better estimates within populations considered chronically underdiagnosed: girls, children of color, and children from low socioeconomic backgrounds. (While autistic adults are also underdiagnosed for a variety of reasons, the 1 in 45 rate is from a parent survey about autistic children.)

All this evidence refuting an autism "epidemic" is (or should be) common knowledge, to those who follow mainstream autism research even casually. But that hasn't stopped some people and organizations from publicly complaining that these numbers are irrefutable proof of a "catastrophe."

A charitable perspective on such denialism is that the doomsayers in question are concerned about the increase in actual numbers of autistic kids and adults who need and aren't (or won't be) getting enough support, due to population increase combined with prevalence, and divided by insufficient funding. If their motives are indeed humanitarian, then I'd like to remind those folks that is it possible to lobby for needed funding and supports without worsening the negative public perception of the very people those organizations and their leaders are supposed to be championing.

As Silberman said to Terry Gross on NPR's Fresh Air, regarding the harm of an "epidemic" mindset and cure-focused approach to autism, and how that negative misinformation disproportionately affects how autism funding is directed:
"What I say is that at least some of that money should be redirected to things like helping autistic adults live more satisfying, healthier and safer lives, or helping families get the services they need or helping families get a quicker diagnosis for their kids."
Refuting the idea of an autism "epidemic" and fighting like hell to help get autistic people the supports they need and deserve shouldn't be mutually exclusive efforts. Now that you know what the new 1 in 45 numbers represent, please do speak up when anyone uses those new numbers for misguided or hurtful purposes.


[Edit: A previous version of this article attributed the 1 in 45 numbers to a CDC survey. They are in fact from a National Health Interview Survey (NHIS).]