Prof. Peter Bearman interviewd by Tom Insel

21 Apr

Prof. Peter Bearman is a sociologist at Columbia University who has undertaken a monumental task: figure out what is behind the increase in autism prevalence. He has chosen (at least so far) to work with California Department of Developmental Services data. This dataset is no where near the “gold standard of autism epidemiological data” that some have touted it to be. But it remains as one of, if not the best, dataset in the US.

I wrote about his most recent paper in Social influences on the rise in autism prevalence and Diagnostic change and the increased prevalence of autism.

Given the importance of this work, I thought it worthwhile to present this short interview of Prof. Bearman by the NIMH Director and IACC chair, Dr. Tom Insel. It is significantly shorter than the full lecture I linked to, and it is possible to embed it:

Prof. Bearman’s team is working on analyzing the California Department of Developmental Services (CDDS) dataset to see what trends can be identified.

Ascertainment, change in diagnostic criteria, increases in parental age, socio-demographic changes are factors in the increase in prevalence.

For example, in the past, it was wealthy families who were more likely to obtain an autism diagnosis for their child. Now that socio-economic divide is disappearing. This is a sign that ascertainment has been an effect.

Professor Bearman notes that some effects have been quantified:

25% of the increase is diagnostic change on the border between autism and mental retardation
16% of the increase is diagnostic change on the other border–between autism and other disorders
3% spacial clustering
11% increased parental age

Prof. Bearman suggests that the increased parental age factor is likely genetic in origin. Increased parental age leads to more copy number variations (CNV), leading to more autism.

I don’t expect this to change the “there can’t be a genetic epidemic” slogan. At this point it isn’t proven that this large factor is genetic. But it is possible.

There is still a large fraction of the increase which is unaccounted for. Prof. Bearman warns at the end that a search for a “quick and dirty” answer may not be advancing science.

I take “quick and dirty answer” to mean vaccines.

The problem is highly complex. The next steps in this study will be very difficult. The social influences on increasing autism prevalence can amplify other factors. Finding possible causes for a real increase in autism incidence will be complicated by other factors. But unless someone quantifies and understands those factors, the likelihood is very low of ever finding causes of autism which might drive part of the increase in prevalence.

11 Responses to “Prof. Peter Bearman interviewd by Tom Insel”

  1. Liz Ditz April 21, 2010 at 22:16 #

    Does “ascertainment” mean “finding, counting, and labeling the people who have a given condition”?

    It’s a little bit different than “better diagnosis”.

    I mean, I think that is what it means, but I’m not sure.

  2. Joseph April 21, 2010 at 22:44 #

    @Liz: The term “better diagnosis” is a straw-man, intended to impress and distract. The only ones who use it, as far as I can tell, are anti-vaxers.

    Awareness, for example, doesn’t have anything to do with the ability to diagnose correctly or differently. It’s not sufficient for someone to be able to diagnose the condition. People also need to seek a diagnosis.

  3. Liz Ditz April 21, 2010 at 23:36 #

    I phrased my question awkwardly. I really was seeking an accurate understanding of what “ascertainment” meant, as Bearman used it, because I’m not quite sure of the exact meaning in that context.


    Uh oh, I might be an anti-vaxer without knowing it.

    I certainly use “better diagnosis” in casual conversation, especially with people who aren’t sophisticated about the issues, like this imaginary bit of dialog:

    “Well, Sally, part of the increase is better diagnosis. For example eople who used to be labeled ‘mentally retarded’ might now have an autism diagnosis. Also, people who might not have a label 20 years ago, but who had issues, now know what the deal is.”

    Yes, I know that the former is really “diagnostic substitution” and the latter is (probably) “diagnostic expansion” — but when I’m are at somebody’s dinner party (for example), I don’t feel the need to be extremely precise. It’s a first pass, and you want to get the ideas across not the exact terms.

  4. Joseph April 22, 2010 at 02:06 #

    Well, anti-vaxers do use it a lot. Try this in Google: “better diagnosis”

    Ridiculous, isn’t it?

    Ascertainment in this context generally appears to refer to case-finding (which could be passive, i.e. “you find us”) plus diagnosis methods (which could be “show us your documentation.”)

  5. LAB April 22, 2010 at 03:08 #

    Prof. Bearman makes a distinction between a diagnosis of “autism” and a diagnosis of “autism spectrum disorder” (incl. Asperger’s, PDD-NOS) and talks about the “cluster” in California of autism (not ASD) diagnoses and what may be causing it. One thing I’d note is that there is no real standard for diagnosing “autism” vs. ASD (some doctors will give a diagnosis of “autism: high functioning,” for example, which could just as well be ASD, yet technically falls under “autism”). I would also say that the younger a child with symptoms is diagnosed, the greater the likelihood that he will receive a diagnosis of “autism” vs., say, Asperger Syndrome.

    When my son was three, he was diagnosed with “autism” by a respected developmental pediatrician. The following year, my son went through two different University-based evaluations, both of which concluded that he had Asperger Syndrome (although one of them was on the fence, finding my son somewhere between “autism” and Asperger Syndrome). So does my son still have “autism,” as he did at age three, or does he have Asperger Syndrome? Or does he not have Asperger Syndrome at all, but instead this mysterious thing called “high-functioning autism”? All of this stuff really muddies the waters when you’re talking about who has “autism” and who has ASD.

    I think Prof. Bearman is correct when he opines that the California “cluster” could be the result of vigilance in the community and among parents (i.e., friends, relatives, neighbors, daycare workers recognize the symptoms earlier and kids are getting diagnosed younger, with the younger age leading more often to an “autism” diagnosis rather than Asperger). You find lots of kids who receive a diagnosis of Asperger Syndrome at age 7 or 8. However, if that same child had been born in an area hyper-aware of autism symptoms for whatever reason, he may have been diagnosed at age 2 or 3, and probably then with “autism” and not Asperger’s. This reality is also an integral part of the “recovery” scene–a child who goes from “autism” to Asperger’s in the span of a year or two. Is it recovery, or is it more about age of diagnosis?

  6. LAB April 22, 2010 at 03:17 #

    BTW, Age of Autism generally uses “better diagnosis” sarcastically, as a way to scoff at the “other side” for not buying their vaccine-related epidemic claims (i.e., “Oh, right, I forgot. It’s not the poisons we’re injecting, it’s all just better diagnosis!”). They tend to bring up “better diagnosis” simply to mock the idea.

    • Sullivan April 22, 2010 at 04:37 #

      Then again, LAB, the people at the Age of Autism think that when one doctor is given ethical approval to take two extra colonoscopy samples from patients where colonoscopies are clinically indicated, that covers lumbar punctures and performing colonoscopies on patients whose symptoms don’t call for such an invasive procedures.

  7. Joseph April 22, 2010 at 14:57 #

    Corollary: Harold Doherty is an anti-vaxer. Demonstration follows: “better diagnosis”

    Ta-da! 🙂

    No, seriously, look at those results. What the heck is his deal?

  8. passionlessDrone April 22, 2010 at 18:17 #

    Hi Joseph –

    I’m surprised that you would perform such a prefunctory analysis. The quote is part of a quote on his page that gets loaded with every single blog posting he does. He only typed it once, google is just being efficient in the wrong way.

    The style of his blog, perhaps we can question, but as far as what the heck his deal is, this doesn’t tell us too much.

    – pD

  9. Joseph April 22, 2010 at 18:43 #

    Yes, I noticed. But silliness aside, Harold is indeed an anti-vaxer who likes to pretend he’s just asking questions, etc.

    • Sullivan April 22, 2010 at 19:42 #

      Keep in mind that Harold Doherty lost his privilege to participate in the discussions here, so he can’t respond. I think it is pretty clear I don’t agree with him on many counts.

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