The Autism-Mercury issue--Reviewing the 2001 Article

Because there has been so much news coverage in the past few years about a possible link between thimerosal-containing vaccines and autism, one might think that this thesis had been around since Noah began building the Ark. In fact, the link was suspected first in the early-to-mid 1990s. This suspicion, nurtured by a group of parents who went on to form Safe Minds (safeminds.org) in 2000, led the government in 1999 to order childhood vaccines (except one influenza vaccine) be thimerosal-free by 2001. Though the government publications characterize this 1999 decision as motivated by an 'abundance of caution,' Safe Minds advocates and their supporters took this not simply as a signal victory for their fledgling organization but as an admission by the government of the harm that thimerosal-containing vaccines was doing to our children. Lyn Redwood, an RN who is now President of Safe Minds, argued, for example, that the childhood vaccine schedule in 1999 would have exposed her (autistic) son to dosages of mercury more than 100 X the federally-recommended levels.

But what gave more life to the mercury-autism theory after the banning of thimerosal-containing vaccines was an article authored by Sallie Bernard, Lyn Redwood and several other parents of autistic children in 2001, which appeared in Medical Hypotheses and was entitled "Autism: A Unique Type of Mercury Poisoning" (easy to find online). The article, combined with reporter David Kirby's 2005 book Evidence of Harm, arguing the same mercury-autism link, created quite a stir in the autism world, and continues to be argued by many. The thesis, in short, is that the autism "epidemic," as many in the field call it, of the last two decades has been triggered in large part by the increasingly toxic mercury-containing vaccines, vaccines which, when combined with unidentified childhood genetic susceptibilities, produced autistic-like conditions in many children. In fact, the thesis runs, autism is, like "mad hatter's disease" in the 19th century or "acrodynia" (pink disease) among babies in the 20th century (the rubbing of teething powder laced with mercury caused fever, rash, enlargement of the spllen and lymph nodes, among other things), and is simply a current-day expression of reactions to this mercury overload in children's systems. That all children don't develop autistic symptoms is not a counterargument; the fact that many do, and have developed these symptoms precisely when the incidence of mercury-containing vaccines has also risen, is enough to convince the authors, and many others, of the vaccine-autism connection.

Developing the Thesis

The lengthy and well-researched article summarizes many of its conclusions through a series of tables. We get the "tone" of the thesis by looking at one of them, such as Table A: "Summary Comparisons of Characteristics of Autism & Mercury Poisoning." On the left-hand column are signs of mercury poisoning; the right-hand column lists features of autism. Among psychiatric disturbances brought on by mercury poisoning are: (1) social deficits, shyness, social withdrawal; (2) depression, mood swings, mask face; (3) anxiety; (4) schizoid tendencies, OCD traits; (5) lacks eye contact, hesitant to engage others; (6) irrational fears, etc. Then, the table goes on to list signs of mercury poisoning in speech, language and hearing deficits; sensory abnormalities; cognitive impairments; unusual behaviors; visual impairments; physical disturbances, gastro-intestinal disturbances; abnormal biochemistry; immune dysfunction; CNS structural pathology; abnormalities in neuro-chemistry; EEG abnormalities; and population characteristics.

I list all these categories, which themselves are often broken down into five or ten sub categories, to show the immense ambition and scope of the article. It seeks to draw a complete correspondence map between symptoms of mercury poisoning and autistic symptoms. For, after you read the bewildering and mind-numbing number of characteristics of mercury poisoning, it just happens that there is almost a precise 1:1 correspondence with those afflicted with autism in the right-hand column. The correspondence seems so precise that one's initial reaction is to wonder whether characteristics have been "massaged" in many cases to try to show an identity between the two...

Divining Mercury

But how do we know that a person actually is suffering from mercury poisoning? There is no "test" to determine this, and so a variety of factors have been used to answer the question. Bernard et al. list the following: (1) Observation of impairments in many of the following domains: (a) movement/motor disorder; (b) sensory abnormalities; (c) psychological and behavioral disturbances; (d) neurological and cognitive deficits; (e) impairments in language, hearing and vision; and (f) miscellaneous physical presentations. Then, there is (2) a known high exposure to mercury; (3) detectable amounts of mercury in urine, blood and hair; and (4) improvement after chelation therapy. What the paper seeks to do is to show, based on these four diagnostic criteria, that many if not all cases of autism meet the requirements for mercury poisoning. Indeed, what the paper claims to do is to delineate a single mechanism for inducing all of the primary domains of impairment listed above, and to identify that mechanism as arising from the "environmental insult" of early childhood exposure to mercury. This exposure route, the article claims, is through thimerosal, which is nearly 50% ethylmercury by weight--the preservative in many childhood vaccines.

Critique

The article is too vast to be assessed here in detail. Suffice it to say that the authors have marshaled an immense array of data that seems to show correspondence in behavior between those afflicted with mercury poison and autistic individuals. But the article opens itself up to falsification, on the one hand, and seems to me to try to paint a very fine picture with a four-inch paint brush. That is, its insistence on thimerosal as the culprit in inducing mercury poisoning, which problem is the major cause of autism, is vulnerable on every point of the neatly-linked thesis. First of all, let us say that thimerosal is completely removed from childhood vaccines, which it was by 2001, even though Safe Minds folk argue that some supplies were perhaps not thimerosal free until much later. Wouldn't it seem to follow that one should see a plummeting rate of autism in the years following 2001? Though it is still too early to get definitive figures on this, preliminary data isn't encouraging for the Safe Minds folk. It seems that CA's autism rate continues to climb, even though the rate of increase might not have matched that of the late 1990s. But the only time true believers expect the rates of things to continue to increase at the same rate for all time is in Ponzi schemes.

Then, there is the issue of historical argument and correspondence of symptoms. The authors try to argue that this iteration of mercury poisoning is just another in a long line of them since the 19th century. They give the example of the "mad hatter" from Lewis Carroll's Alice in Wonderland as a person suffering from mercury poisoning and, indirectly, from symptoms similar to those of autism-sufferers. But this ignores the scholarship on Alice in Wonderland suggesting that Carroll's portrait of the hatter is not an accurate portrait of one afflicted with mercury poisoning.

The previous point is a sort of quibble, but it is indicative of the article's attempt, in my judgment, to squeeze a very complex phenomenon (autism) into the fairly tight-fitting strait-jacket of mono-causal explanation. For example, since 2000 much effort has been expended to try to explain the nature of mercury toxicity that may afflict those with autism. Is there a difference between our system's response to ethylmercury and methylmercury, for example? The latter is ingested from fish, the former from thimerosal and other things. Again, isn't it a bit questionable to try to say, for example that since some sufferers of mercury poisoning are depressed, and some autism sufferers are depressed, that these characteristics "map" onto each other? If one became depressed because one lost a friend, and another became depressed because she failed a test, do we conclude that there is a similarity between losing a friend and failing a test? Of course the number of seeming similarities is much vaster than this, but if the nature of the "mappings" or "correspondences" is tenuous, multiplication of apparent overlaps doesn't make your case any firmer. It makes it squishier.

Conclusion

Perhaps one indication that the mercury-autism link is losing steam is that David Kirby, the award-winning author of the 2005 Evidence of Harm, touting the mercury-autism connection, has not said much on that subject lately. He is off trying to show that autism is connected with mitochondrial damage or susceptibility.

In fact, I think that in autism we are dealing with a phenomenon that is so elusive, yet alluring, that when we grasp onto one possible correspondence, we tend to spin out a theory about how it explains the entire phenomenon. But we are still like the six blind men from Hindustan, all feeling the same elephant and concluding that it is was a rope, a fan, a tree, a snake, a tree, or a wall. All said something right, but all were terribly wrong. I think that is where we are in 2008 on autism....still.

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