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April 2009

Medication Treatment for BPD: The Limited Evidence Base
Antipsychotics, especially olanzapine (Zyprexa), may be beneficial in treating borderline personality disorder, but the data are limited and mixed.

Chelation Therapy for Autism?
A study of chelation therapy for autism was stopped due to potential adverse effects.

Varenicline for Smoking Cessation
Varenicline (Chantix) should be used with caution in psychiatric patients attempting to quit smoking.

Minocycline for Schizophrenia: Preliminary Results
The results from an open-label study of minocycline (Solodyn and others) suggest benefit in the treatment of schizophrenia.

In Brief
Modifying risk factors can help prevent dementia; Increased lighting improves cognition in elderly

Chelation Therapy for Autism?

April 2009

The National Institutes of Health (NIH) recently stopped two clinical trials, both designed to test chelation therapy.1 One was to assess the possible benefits of chelation for autism; the other, for coronary artery disease.

Chelating agents, which bind and remove heavy metals (eg, lead, iron, mercury, and arsenic) from the body, are approved by the US Food and Drug Administration for treating acute toxicity of heavy metals. According to the National Center for Complementary and Alternative Medicine, off-label uses of chelating agents contribute to an estimated 800,000 physician visits annually.

One theory about autism maintained that it could be caused by mercury-containing vaccines, which are no longer in use. Although this hypothesis was rejected by most scientists, it spawned the idea that removing mercury from the body could improve social reciprocity and language skills in children with autism. Because of the widespread use of this treatment, despite the lack of scientific evidence for it, the National Institute of Mental Health sponsored a trial in which 120 children with autism spectrum disorder and detectable, although not toxic, blood levels of mercury or lead were to be randomized to receive either a chelating agent (succimer) or placebo.

However, results from a rodent study released in 2006 showed that although chelation with succimer improved learning, attention, and arousal regulation in laboratory animals, it also caused lasting cognitive impairment.2 This led the NIH to cancel the study before it enrolled subjects out of fear that there were limited prospects for therapeutic benefit but real potential for harm.

Enrollment was halted on the Trial to Assess Chelation Therapy (TACT), which is evaluating the approach for coronary artery disease, due to allegations of improper consent forms, including no mention of the risk of death and a conflation of the drug disodium ethylenediaminetetraacetic acid (EDTA) with calcium disodium EDTA. The team of doctors who requested that the US Department of Health and Human Service's Office for Human Research Protections stop the trial called the therapy "unethical, dangerous, pointless, and wasteful." Subjects already enrolled will continue in the 5-year study.

1Mitka M: Chelation therapy trials halted. JAMA 2008;300:2236.

2Stangle DE, Smith DR, Beaudin SA, Strawderman MS, Levitsky DA, Strupp BJ: Succimer chelation improves learning, attention, and arousal regulation in lead-exposed rats but produces lasting cognitive impairment in the absence of lead exposure. Environ Health Perspect. 2007;115:201-209.