Sunday, February 22, 2015

Yes, Virginia, Pesticides DO Cause Autism

I’m no stranger to autism.  Way back in the eighties (or early nineties?) someone invited me to an autism conference.  With dropping jaw I listened to Liz Bates, a prominent linguist now alas deceased, telling the audience that autism was caused by mothers failing to make eye contact with their babies.  That night, in the home of an autism-stricken family, I heard some horror stories including one of a child of three, normally developed until then, not just speaking fluently but speaking three languages, who suddenly and for no apparent reason turned into a speechless affectless obsessive-compulsive in a matter of weeks.

At that time I was more interested in the language of autists than anything else, and then only so far as this afforded a window into the structure of language.  Well, it proved a very murky window, and I had other things to do.  But I remained interested in late-onset autism—like the poor trilingual kid had—because it didn’t match the story that autism was purely genetic.  It seemed blatantly obvious that some environmental factor came into play, probably interacting with a genetic predisposition but still the main culprit in such cases, if only because it was evitable.  I wrote to various autism journals to drum up some interest.  If as I suspected there were two kinds of autism, differently generated, researchers should take note of that.  But no-one seemed interested.

Fast-forward to 2010, when while blogging for Psychology Today, “Autism Awareness Month” came up.  After criticizing its unusually incompetent handling in a PBS “Frontline” and reviewing the vaccine explanation (not proven, I judged, but not entirely disproven either) I wrote:

   “There are countless reports of children as old as three with normal development who suddenly lose language and social skills and regress to an autistic state. What percentage of the autistic community do these represent? We don't know. Nobody seems to be looking, because vaccine defenders tell us it's an illusion. One story was that parents just didn't notice their child's abnormalities until too late. This story, deeply insulting to any parent, has been replaced by a milder version; the "regressing" children had actually, all along, shown "subtle signs" of abnormality that only expert eyes could spot (remember the old bio-lab adage," Believing is seeing"?) Vaccine defenders seem determined to cling to the Gospel of Genes and rule out any environmental causes.
     “As for the numbers, we all know them--at least a twentyfold increase in a quarter-century. Sure, some of that increase is due to broadening definitions, to the inclusion of many milder cases plus some that would have been diagnosed as simply ‘retarded’. But if that was the only factor involved, if there was no environmental input into later developmental stages, the number of cases that would have been classified as autism in 1985 should have remained more or less constant until today. Have they? We don't know. Moreover, rates in California started to rise steeply in 1988, six years before DSM IV broadened the definition.”

Oh, California!  In those days I knew next to nothing about pesticide spraying and GMOs, and I certainly didn’t realize that California was maybe the most sprayed state in the country, hence a natural experiment for testing the effects of pesticides—on, among other things, the incidence of autism.

Since 2010, of course, autism rates have kept on rising.  We’re still told “it’s all genetic” and “the increase is due to the changed criteria”.  Well, as I pointed out in the quote above, the rise in autism in California preceded the broadened definition by six years.  I’m not disputing that this definition, which turned “Autism” into “ASD” (Autism spectrum disorder) did increase the numbers.  But by more than two orders of magnitude?  Don’t insult my intelligence.

Well, to no particular fanfare, and way under the pro-GMO radar, UC Davis launched the program CHARGE (Childhood Autism Risks from Genetics and the Environment) in 2003 as “the first comprehensive study of environmental causes and risk factors for autism and developmental delay.”  Their site ( explicitly states, contra the professional autism community, that neither genes nor broadening criteria could be the sole cause of the monstrous increase in autism diagnoses.  Moreover, while discounting the possibility that any single factor could be responsible, it places the finger of blame squarely upon environmental factors that presumably triggered inherited predispositions.

Well, one of those factors turns out to be (roll of drums, surprise surprise) PESTICIDES! 

The crucial paper (not CHARGE’s only one, btw) is Janie F. Shelton, Estella M. Geraghty, Daniel J. Tancredi, Lora D. Delwiche, Rebecca J. Schmidt, Beate Ritz, Robin L. Hansen, and Irva Hertz-Picciotto (2014) Neurodevelopmental Disorders and Prenatal Residential Proximity to Agricultural Pesticides: The CHARGE Study. Environ Health Perspect; DOI:10.1289/ehp.1307044, available at  (notice the nih in the URL?).  They start the ball rolling by pointing out that 200 million pounds of pesticides are sprayed in California every year, which makes it a natural laboratory for toxicity studies, and in that first paragraph alone they cite no less than twelve papers that show some form of “abnormal and impaired neurodevelopment in children”, one of them relating specifically to ASD and one to ASD’s broader diagnostic category PPD (Pervasive Developmental Disorder).  The study is based on more than 1,600 participants “whose parents answer extensive questionnaires regarding environmental exposures including their place of residence during pregnancy. Here we report on ASD and DD (Developmental Delay) in relation to gestational residential proximity to agricultural pesticide applications”.

After discussing a number of possible confounds and explaining very carefully how the protocol dealt with these, the authors arrived at the following conclusion: “For exposure (any vs. none) during pregnancy, children with ASD were 60% more likely to have organophosphates applied nearby the home than mothers of TD (Typically Developing, i.e. “normal”) children. Children with DD were nearly 150% more likely to have carbamate pesticides applied near the home during pregnancy” [my italics, DB].

In other words, even the slightest exposure to organophosphates could increase the possibility that autism would occur—which of course is exactly what you would expect, given the facts reviewed in “Unsafe at Any Dose”.   More convincing is still is the fact that different pesticides cause different probabilities of damage, showing that this is not a “one-size-fits-all” denunciation of pesticides but one that suggests, again as you might expect, that different chemicals affect different developmental processes to different degrees of intensity.

What are those processes?  We don’t know yet.  Why not?  BECAUSE WE STILL DON’T KNOW WHAT CAUSES ANY TYPE OF ASD!!!  In other words, Shelton and co. are at the cutting edge of science, and the facts that they have unearthed should make it all the easier to ultimately track the precise developmental pathways whose disruption triggers autism.

“But wait a minute,” GMO defenders will predictably say, “is this Real Science?  Bet you it was in another junk journal!!!”

Not.  Environmental Health Perspectives is “published with support from the National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health, U.S. Department of Health and Human Services…It is a publication of the U.S. Federal Government…With an impact factor of 7.03, EHP is the third-ranked journal in Public, Environmental, and Occupational Health, the fourth-ranked journal in Toxicology, and the fifth-ranked journal in Environmental Sciences.”

“But nowhere in the paper does it mention Roundup or Glyphosate!”

Glyphosate IS an organophosphate.  See the Finnish doctoral dissertation (2009, University of Kuopio) entitled “Fate of the organophosphate herbicide glyphosate in arable soils and its relationship to soil phosphorus status” by Pirkko Laitinen of MTT Agrifood Research Finland, Plant Production, FI-31600 Jokioinen, Finland (you can find this at  So the link’s complete, and the stage is set for my next post, which will discuss the Swanson et al. correlation of glyphosate with autism, nationwide.


  1. Although glyphosate is an organophosphate compound, it seems noteworthy to me that the CHARGE study was referring to organophosphate insecticides, i.e.neurotoxins, along with several other insecticides such as pyrethroids and carbamates. Organophosphate insecticides work by affecting the enzyme acetylcholinesterase. Glyphosate does not have this mode of action.

    Your thoughts?

    1. You may have a point. I'll write the lead author to clarify this. But in and of itself, your point is by no means conclusive because (a) we don't know yet all the possible neural pathways affected by glyphosate and (b) we don't know all the developmental mechanisms that if disrupted can lead to autism. I agree, the answer should be found, and print a correction if one should be needed.

      Anyway, Kent, I'm glad you wrote. I've been trying to contact Andy Buckley to say yes, the only reason I didn't answer his last post on GLP was that when I tried to put my response up I was told I was blocked from the site. That sucks. I had not been offensive, abusive or anything that would be a legitimate cause for blocking--the only possible conclusion is that my remarks were too near the bone for John Entine (I'm assuming that as director of GLP he was the one responsible for blocking me--if I'm wrong, correct me). He, or whoever did it, should realize that such actions are highly counterproductive--they give the impression that GMO advocates are out to suppress any criticism of their beliefs. Anyway, I'd appreciate it if you could contact Andy for me and let him know that he is welcome on my site at any time. Or anyone else who knows how to have a civil argument, as both of you do.

    2. I passed along the message to Andy the only way I know how -- as a reply to the last comment on the GLP Vani Hari article. Hopefully, he'll get a chance to see it.

  2. Except the main RR GMO crops are field corn, soybeans, sugar beets and canola.
    None of which are big crops in California which mainly grows vegetable crops, fruit and nuts.

  3. BIG WHOA!

    Definition of an Organophosate: An organophosphate or phosphate ester is the general name for esters of phosphoric acid.

    Esters are chemical compounds derived from an acid in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group.

    Glyphosate is formulated as an isopropylamine salt. While it can be described as an organophosphorus compound, glyphosate is not an organophosphate ester but a phosphanoglycine, and it does not inhibit cholinesterase activity.

    So it would NOT be in the list of chemicals that they found associated with ASD

    1. Thanks, Arthur. Strictly speaking, you're right. Look out for my next post, an update on this paper following my correspondence with its lead author, where I'll try and set all this straight.