What the Poling Autism Case Means

The widely publicized court victory for the family who claimed vaccines caused autism in their daughter does not prove a link.

Rahul K. Parikh, M.D. March 13, 2008

NIMH Statement on Chelation Trial for Autism Spectrum Disorders

September 17, 2008

The protocol for a proposed National Institute of Mental Health (NIMH) chelation study for autism that has been discussed for the past two years for human subjects' protections has been discontinued. NIMH has decided that resources are better directed at this time to testing other potential therapies for autism spectrum disorders [1] and is not pursuing the additional review required to begin the study.

The chelation study protocol was originally reviewed by an NIH Institutional Review Board regarding the risks and benefits of the treatment and was approved to go forward in June 2006. No subjects were recruited for this clinical trial. In February 2007, based on new scientific data [2], an NIH Institutional Review Board reassessed the risk benefit ratio of the proposed study. The Board determined that there was no clear evidence for direct benefit to the children who would participate in the chelation trial and that the study presents more than a minimal risk. Thus, the only way that the study could go forward would be through an additional approval process by the Department of Health and Human Services (DHHS).

Two years have elapsed since the initial protocol was reviewed for human subjects' protections. The DHHS review process can take as long as one year to complete because it includes review by a pediatric advisory board, the Food and Drug Administration and public commentary. If DHHS were to approve the study for subject recruitment, it is estimated that data collection would take at least another three years. During those four years, it is quite likely that additional research on the basic pathology of autism will provide deeper understanding of the causes of autism and more refined avenues for developing treatments. Given the time and resources required for this additional approval process, NIMH has decided to use its intramural program to test other interventions for autism and will not pursue the required DHHS review.

As a result, the Protocol 06-M-0238: "An Investigation of the Efficacy of Mercury Chelation as a Treatment for Autism Spectrum Disorder" has been terminated.


  1. Current NIMH clinical trials for children with autism
  2. Stangle D, Smith D, Beaudin S, Strawderman M, Levitsky D, Strupp B. Succimer chelation improves learning, attention, and arousal regulation in lead-exposed rats but produces lasting cognitive impairment in the absence of lead exposure, Environmental Health Perspectives 115, Number 2, February 2007.




This article was posted on March 14, 2008.

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