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 http://www.ncbi.nlm.nih.gov/pubmed 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?