Thoughts on the Increase in Autism Diagnoses
Brace yourselves…it’s about to get political…
If you hold a deeply contrarian view on a well observed topic, there’s an important question you should be prepared to answer if you’d like anyone to take you seriously.
What is it that you know that others don’t?
Not what you believe or what you hope, but what you know. If you don’t have an honest answer, then it’s best to stay away from people who have been impacted by whatever topic you hold your contrarian view about. While this is a broadly good principle to live by, it’s particularly good when dealing with the question of what causes autism and the large increase in prevalence observed over the last thirty five years.
It’s been a little over fifteen years since our son was diagnosed with developmental delay and ultimately autism. For years my wife and I ran a nonprofit organization that provided free mental health and counseling services for parents and caretakers of children and adults with special needs. I know many things about autism. But the boring truth about my experience is that the only thing I know that others don’t is our specific journey, which means that I don’t have a deeply contrarian view on the causes of autism. And I don’t have one on the rise of autism prevalence from 1 in 150 in 1990 to 1 in 31 today.
That doesn’t mean that I simply follow the herd like a sheep when it comes to care and treatment for my son. Because we don’t really know definitively what’s going on with him yet. Anything could have happened to him because anything could have happened to one child. And so we often find ourselves trying treatments and therapies that aren’t grounded in tons of data to see if they work. Some have. Most haven’t. But we’ll keep going. The debate we’re all about to embark on is not about one child, though; it’s about millions of children and millions of diagnoses. Which means we can follow the data to the degree that we can declare some things mathematically impossible. Unless there are global conspiracies that transcend decades, regions, cultures and professions, we should feel safe focusing on some causes and moving on from others.
If you believe that the conspiracy is that broad, then why believe the 1 in 31? Or anything? And from there it’s just turtles all the way down. The rest of this essay isn’t for you.
Here’s what we actually know regarding the increase in prevalence of the autism diagnosis.
Mostly, it’s awareness. The expansion of diagnostic criteria to include lower impairment symptoms is the largest slice of the awareness pie. Early intervention diagnosis, particularly in children under two, is the next largest slice. Diagnostic substitution is the next, which is actually what happened to us. Forty years ago my son simply would have been diagnosed as cognitively impaired. At the same time autism diagnoses have increased, cognitive impairment diagnoses have decreased. None of this aspect of the increase is mysterious, and most of it is good. Increased diagnostic outcomes allow for more services and more improvement for kids who otherwise would have been left behind at the most variable portions of their lives. If you believe that these kids just need to tough their way through things, you should read a few books on how psychiatric disorders were treated fifty years ago. (Again, what do you know that others don’t?)
Beyond increased diagnosis, it’s older parents and more kids surviving early term birth; both good things. Which means that for between seventy five and eighty percent of the increase, there’s no bad guy. Which is really, really hard to sell as a story. I told you I was going to be boring.
Now on to the bad guys, or at least the space where some might hide.
We’re left with environment, gene interactions and mysteries to solve the last twenty to twenty five percent, which represents millions of children, so we should care a lot about them.
First, what it’s not: vaccines. There are scores of studies involving millions of children conducted by scientists who have asked the questions and normalized for the sorts of factors that would allow for the size of impact needed to explain the other twenty to twenty five percent of the increase. Children do get injured by vaccines. We know this, and it’s not even controversial. But the upper bound for what could be hiding in the data is about 1 in 2 million kids. In trying to explain an increase from 1 in 150 kids to 1 in 31 kids, it doesn’t work.
Genes mutations really don’t move at the rate required to support the left over increase over thirty five years. It’s also not one single known smoking gun pollutant. Nothing introduced in the last thirty five years has been found to have the level of impact needed to explain the final percent increase. That doesn’t mean we won’t find something. Just that we haven’t, and it hasn’t been for lack of looking.
So here’s where we are. We know the brain is a complicated thing that it doesn’t take much for the highest level of development to be knocked off baseline enough to cause impairment. And we know there’s a whole lot of things in the world today that weren’t there before. So something is driving that last unexplained amount. But we actually don’t know yet.
The reason I’m writing this now is that the increase in autism rates is about to become very political. Which means there will be people who can gain or lose power based on declarations made. That’s very likely to muddy the water. My advice is to look for the new information. Scientific discoveries don’t happen without new information or new analysis with old information. Which is really just the same thing as asking what your present self knows now that every person living in the past doesn’t. If the answer is nothing, than it’s likely just politics. And I’m too busy caring for my son and the community of caretakers to care.
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