NIMH Chelation Study

Two weeks ago I wrote to Karin Lee at the National Institute for Mental Health (NIMH) press office after reading a press release that said that NIMH was going to conduct a trial to see if chelation therapy improved the behaviour of autistic children.

I asked what I thought was an obvious question.

Can you point me to any published research that demonstrates that autistic children do have elevated levels of heavy metals in their blood?

I wanted to know if NIMH had any evidence that blood levels of mercury are higher in autistic children than their neurotypical(NT) peers. To judge from Karin’s reply, NIMH do not have any evidence. Instead of giving me references Karin suggested that I

conduct a search on PubMed, a service of the National Library of Medicine. To access PubMed go to the Web site and type your topic in the search field.

Thank you Karin. I do know how to search PubMed. I found a recent study that showed no difference between mercury levels in autistic and NT children. I found another study that gave reference values for mercury in the blood of children as 1 microgram per litre (1 microgram =1 millionth of a gram) and for lead as 50 micrograms per litre. Karin also refered me to a more detailed description of the clinical trial. This contains the following inclusion criteria.

  • Male or female subjects, four to ten years of age.
  • Meets research criteria for ASD (specifically, autism, Asperger Disorder, or Pervasive Developmental Disorder – Not Otherwise Specified).
  • Detectable (greater than 0.1 microgram per deciliter) levels of blood lead and/or blood mercury.
  • Each legal guardian must have a level of understanding sufficient to agree to all required tests and examinations. Each legal guardian must understand the nature of the study and must provide written consent to study protocol.

Note the figure for levels of lead or mercury is equivalent to the reference figure for mercury of one microgram per litre and way below the reference point for lead. These levels are so tiny that everybody has them. Here are the exclusion criteria.

  • History of allergic reaction to sulfur or thiol-containing substances
  • History of previous chelation therapy for autism
  • History of uncontrolled epilepsy
  • Weight less than 15 kg at screening
  • Presence of a chronic medical condition that might interfere with study participation or where study participation would be contraindicated or clinically significant abnormal baseline laboratory results.
  • Level of lead above 10 microgram per d, or Level of mercury over 44 microgram per deciliter (toxic levels which require intervention with chelation and preclude placebo assignment) or other evidence of heavy metal toxicity.
  • Recent (less than two months prior to study entry) initiation of behavior therapy

Note that autistic children with heavy metal poisoning are not eligible for this study. They need treatment and it would be unthinkable to put them on a placebo. But this means that to be eligible for a study in which you may be treated for heavy metal poisoning you must be completely healthy and not have heavy metal poisoning.

Autistic children with traces of heavy metals in their blood that are no different from the levels in NT children are going to be subject to unnecessary medical treatment to see if it alters their behaviour. Well, it would certainly alter mine!

I wonder why they are only recruiting autistic children? Perhaps NT children with the same reference levels of mercury would also benefit from a dose of chelation therapy. But what self respecting parent of a healthy child would submit their child to that? And that goes for the parents of healthy autistic children as well.

I am guessing that NIMH will only attract parents who believe their child is sick. They believe their child is mercury poisoned. NIMH will have to have a very good screening programme to exclude parents who have already tried chelation on their child. I am guessing that, even then, they will only attract parents who are already using other biomedical interventions. There is nothing in the description of the clinical trial that takes account of any of the other possible confounds arising from unorthodox biomedical interventions.

There is a final ethical consideration I would like to raise.

Parents approach DAN! practitioners with a false belief about their child’s health, seeking treatment for that child. The DAN! practitioner shares their belief and provides the treatment.

Parents approach a NIMH doctor with a false belief about their child’s health, seeking treatment for that child. The NIMH doctor does not share their belief. In fact they have to establish that the child is not ill. But they still provide the treatment requested by the parent.

Who has made a moral decision here; the DAN! practitioner or the NIMH doctor?


15 thoughts on “NIMH Chelation Study

  1. If I was still alive, I’d be able to spot the mercury poisoned kids easily. They’re much different from the kids with genetic problems.

  2. A good study design would include NT children who meet the other criteria, as control groups for those receiving the treatment and those receiving the placebo. In other words, we would need to be able to see if receiving either treatment causes any particular behavioral responses; otherwise it is too easy to assign any and all additional behaviors to autism and/or mecury/heavy metal contamination/poisoning.

    As you point out, there are a number of additional confounds, such as other treatments being used, both medically and behaviorally.

    This does not look like a well-designed study.

  3. I think the study is mostly fine. If there’s no breach of the double-blind, it should tell us if DMSA is different to placebo when it comes to autism and/or mercury levels above the reference value.

    The only problem is the lower limit in blood mercury levels (and I realize this is the opposite of what the post argues). The study is basically pre-selecting children who do have mercury concentrations above the reference level, and who could therefore be more responsive to DMSA than random autistic children.

    That said, given the upper limit in blood mercury levels, and prior studies on chelation for low-level lead exposure, I expect the results will indicate DMSA is, at best, as effective as placebo.

  4. Hi Joseph,
    my point was that if they are going to take any autistic child with detectable metals above the reference level but below the level for heavy metal poisoning they will be chelating a lot of healthy children who do not need chelating.

    The research may produce some interesting results. But I still think it is unethical.

  5. I have to admit, as a PhD pharmacologist, that the study is designed properly, but the real question is the selection of subjects. The question you asked initially is the real one. Is there any real evidence that heavy metal poisoning causes autism? According to the research you have uncovered, the answer would be NO. I tend to agree. If there is no evidence to support the reasoning behind the therapy, why test it? That is not only unethical, it is also a waste of research funds! But then again, the reason I no longer conduct research is that I got tired of “supporting” mentor scientists who used any excuse to get a grant-whether or not they had a valid “educated guess” of a hypothesis!

  6. Very untrustworthy sampling techniques

    after that the study to be conducted properly would have to be unethical in the extreme, because to prove chelation works, no other intervention would have to be practised, no school, no communication, no nothing as that might skew the study.

  7. I think many DAN critics tend to throw the baby out with the bathwater. Much commentary from the anti-DAN camp assumes all parents just go along, following any wacky practitioner and damn the consequences. It can’t be denied that there are people who’ve been able to improve their children’s health and quality of life through biomedical interventions combined with traditional therapies and working with a good practitioner. I know a few parents and children who are seeing positive results.

    Our 9-year-old son has benefited from some of the DAN recommendations, begun when he was 2. We didn’t expect a reversal of our son’s condition and no one told us to expect that–simply improvements that increase his quality of life and make our family life less challenging. For example, on a gluten/casein-free diet with a few supplements our son has more receptive and expressive language and I deal with about 6 behavioral problems (like walking the kitchen counters) in an afternoon instead of 18 incidents.

    We did our own amateur research to be sure it wasn’t coincidental by beginning the biomedical interventions, establishing that he had improved by charting behaviors, getting feedback from teachers and therapists added to our own observations, then removing them and watching him regress. Everyone noticed. It was difficult but, I thought, necessary to be certain that we should proceed with DAN-influenced recommendations from our son’s board certified, respected pediatrician who attends the conferences.

    Our son has not had chelation and we’re planning to give transdermal chelation a trial fairly soon. I have a friend who takes her daughters for IV chelation treatments–which make me feel uncomfortable–but she’s met several people at the clinic whose children are in treatment and have made noticeable language and social gains since beginning their treatments. One of her daughters has increased language and social awareness and the other has shown no change.

    Just another perspective…

  8. Thanks Julie

    when I began this blog a year ago I wrote:

    But let’s not dismiss the whole shebang as being about gullible parents who are ripped off by snake oil merchants. Some children do regress after an apparently normal early life. Autistic people do experience atypical responses to all sorts of environmental inputs, including medications. Autistic children do contract painful gut disorders. Some autistic people do benefit from restricted diets.


    The first thing we have to be clear about is that the child’s symptoms are real. Some parents have had their worries dismissed because it is assumed that autistic children will have poor sleep patterns, scream a lot and be difficult to feed anyway. It is experiences like this that explains some parental support for Andrew Wakefield and his theory of the MMR link to autism. If memory serves, Nick Hornby author and a father of a son with autism, stated that he had no axe to grind regarding MMR but the doctors at the Royal Free were the first to take his son’s gut disorder seriously and offer him treatment.

    The second point is that some of these symptoms may be connected to a child’s autism. But we do not know how. If you are non-verbal and you have constant earache, you will head-bang. That does not mean that your earache caused your autism. Nor does it mean that alleviating your distress will cure your autism. It means you are autistic and you have an earache.

    Anyone with an autism diagnosis should be given a full medical work up in case there any other conditions that need treatment. Too often the diagnostic process stops when autism is identified. There are autistic children who have other conditions that may respond to safe, targeted biomedical interventions.

    I do not include chelation in this category. sorry. There is no credible science to support it. Until I see a credible hypothesis that suggests how the mercury in vaccines, which is measured in millionths of a gram, could cause massive accumulations of mercury in the body and lead not to mercury poisoning but to autism, until then I will oppose the experimentation on our children.

  9. I agree it’s a very controversial approach. And, yes, it’s frightening to think how easily one could overlook something that’s causing autistic symptoms without a thorough medical work-up. I remember feeling like my son and I spent much of his second year of life at the local Children’s Hospital giving blood, doing EEG, MRI, etc.

    I must say you’ve accumulated a great amount of knowledge. I don’t encounter many men who’ve delved into learning more about autism; although, attending large conferences helps me realize that it isn’t only the mothers learning and trying to help their children.

  10. “Those who believe that autism makes someone less than human often talk about it having stolen the child’s soul.. ”

    Hmm, I would like to meet these people as I would beat them with a big stick.

    Do you know of such persons?

    “Anyone with an autism diagnosis should be given a full medical work up in case there any other conditions that need treatment.”

    As you rightly state, the above should be the case but what actually happens is diagnosis then handed over to education, no medical tests.

    “Can you point me to any published research that demonstrates that autistic children do have elevated levels of heavy metals in their blood?”

    Mercury is absorbed readily into cell tissue, so mercury levels are not accurately detected in blood.

    Parents have the right to use approved treatments for their autistic children.

  11. Mike,

    “Anyone wishing to voice their concerns about NIMH sponsoring a chelation trial for autism should follow this advice from NIMH.

    We suggest addressing your continued concerns to the NIH Office for Human Research Protections (OHRP). ”

    Who is the “we”? I hope your not suggesting it’s the NAS?

    Do any of the parents believe in chelation at the school you teach Mike?

    Does the NAS know your doling out this advice?

    I would have thought the NAS would welcome studies dedicated to proving/disproving treatments for autism, wouldn’t you?

    Since you’re an active member of NAS you should be a little more diplomatic with your unethical opinions.

  12. Kevin is replying here to my comment on Orac’s blog. Sorry for the confusion.

    if you read my comment properly you will see that “we” refers to the NIMH. I am passing on the advice they gave to me.

    With regard to your veiled threats and innuendoes regarding my conduct as a teacher and as a member of the the NAS, either make your complaints to the proper authorities or stop being so silly.

  13. Mike,

    I can do both. If I feel you’re views are at odds with NAS, I will comment. If I feel the need to complain to the proper authorities because I find the comments offensive, then I will do so. I wouldn’t class that as “being silly”. It’s called freedom of speech.

    Remember, you’re an ambassador of the NAS, your school, autistics and to the parents of the autistic children at your school.

  14. Heavy metals don’t directly cause autism but are indirectly implicated in a small percentage of people who have genetic impairments that result in high whole body half-lives (not blood levels). Whats really needed is a better selection of the impaired individuals in the subset of autistic kids who have such genetic deficits. Autism is not 1 but rather a couple hundred genetic impairments that result in elevated half-lives of many chemicals that most people can excrete without harm. Thus low levels of a substance that can have a half-life of 20 days in a normla kid can have half-lives of 200-300 days in the impaired small subpopulation. As a radiologist, I give an IV radiotracer (technetium-99) that is chelated to DMSA and its rout is traced out of the body through the kidneys. A better way to test the idea that heavy metal excretion is primarily and firstly impaired would be to give a comparable dose of radioactive mercury to what we all receive in flu shots and track its biological half-life in autist and normal kids to show that there truly is a difference in metal handling. Then give chelation protocols only in the subset of autistics that are metal impaired (because not all are affected by this some are impaired directly in methylation capacity and others have difficulty in organoophosphate excretion and therefore will not benefit from chelation). Sadly this problem really needs a few great thinking radiologists to help track the metal issues.

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