The hypothesis , A., Roger, T., Binstock, T., & Redwood, L. (2002). The role of mercury in the pathogenesis of autism. Molecular Psychiatry , 7, S42-S43.</ref>. An important problem with this theory is the fact that the symptoms of autism do not perfectly resemble symptoms of mercury poisoning. Though mercury poisoning can cause impaired social interactions, communication problems, and stereotypic behaviors<ref>Bernard, S., Enayati, A., Roger, T., Binstock, T., & Redwood, L. (2002). The role of mercury in the pathogenesis of autism. Molecular Psychiatry , 7, S42-S43.</ref>, as seen in autism, it also causes “ataxia, constricted visual fields, peripheral neuropathy, hypertension, skin eruption, and thrombocytopenia”<ref>Ng, D. K.-K., Chan, C.-H., Soo, M.-T., & Lee, R. S.-Y. (2007). Low-level chronic mercury exposure in children and adolescents: meta-analysis. Pediatrics International , 49, 80-87.</ref> - symptoms not seen in children with autism. Thimerosal, the mercury-containing preservative found in vaccines, has been removed from nearly all childhood immunizations. In one state study, however, the Caifornia Department of Developmental Services found that the prevalence of autism increased from January 1995 to March 2007, concluding that exposure to thimerosal does not lead to autism<ref>Schechter, R., & Grether, J. K. (2008). Continuing increases in autism reported to California's developmental services system. Archives of General Psychiatry , 65 (1), 19-24.</ref>. Nevertheless, caregivers of children with autism have sought out treatment to rid mercury and other heavy metals from the body, in a process known as chelation.

Chelation therapy was used by the British after World War II to remove arsenic, lead, and other metals created by the during the war due to lack of materials. Patients’ conditions improved as these metals were removed from their bodies<ref>Nash, R. A. (2005). Metals in medicine. Alternative Therapies in Health and Medicine , 11 (4), 18-25.</ref>. Today, chelation therapy is used to rid the body of toxic metals such as lead and mercury. Doctors should take a blood test to assess current kidney and liver function, nutrient status, and blood-lipid levels before chelation therapy begins<ref>Klotter, J. (2006). Chelation for autism. Townsend Letter: The Examiner of Alternative Medicine , 30, p. 273.</ref>. A gluten-free, casein-free (GFCF) diet and supplemental changes, including shots of vitamin B12, may be used. Treatment may be applied to the skin via a transdermal patch<ref>Bridges, S. (2006). The promise of chelation. Mothering , 54-61.</ref>. Another treatment is administered intravenously, a process that takes 2-3 hours, costs about $100 per treatment, and 20-30 treatments are often required<ref>Klotter, J. (2006). Chelation for autism. Townsend Letter: The Examiner of Alternative Medicine , 30, p. 273.</ref>.

Some common chelating agents are EDTA (ethylenediaminetetraacetic acid), DMSA (sodium 2,3 dimercaptopropane-1 sulfate), TTFD (thiamine tetrahydrofurfuryl disulfide), and DMPS (2,3 dimercaptosuccinic acid). EDTA and DMSA are only approved for the removal of lead by the Food and Drug Administration while DMPS and TTFD are not approved by the FDA. These drugs bind to heavy metals in the body and prevent them from binding to other agents. They are then excreted from the body. The chelating process also removes vital nutrients such as vitamins C and E, therefore these must be supplemented<ref>Bridges, S. (2006). The promise of chelation. Mothering , 54-61.</ref>.

Some parents of children with autism have reported significant gains in their children’s symptoms following chelation therapy. They contend that within weeks of the initial treatment, their children have made drastic improvements in behavior and social engagement. Younger children have reportedly made faster and more significant results<ref>Bridges, S. (2006). The promise of chelation. Mothering , 54-61.</ref>. However, other parents have stated that chelation therapies made no difference in their children’s developmental outcomes<ref>Laidler, J. R. (n.d.). Through the looking glass: my involvment with autism quackery. Retrieved May 26, 2008, from Autism Watch: http://www.autism-watch.org/about/bio2.shtml</ref>.

There are significant risks associated with the use of chelation for the treatments of autism. The deaths of two children were reported due to hypocalemia and cardiac arrest after receiving chelation therapy<ref>Schechtman, M. A. (2007). Scientifically unsupported therapies in the treatment of young children with autism spectrum disorders. Psychiatric Annals , 37 (9), 639-645.</ref>. Long-term use of the chelating agent SMSA can cause liver damage, zinc deficiency, and bone marrow suppression<ref>Klotter, J. (2006). Chelation for autism. Townsend Letter: The Examiner of Alternative Medicine , 30, p. 273.</ref>. Mineral deficiencies, cardiovascular effects (blood pressure drop), kidney problems, and the possibility of distributing mercury throughout the body may also occur. However, using a combination of chelators, supplements, diet changes, and regular lab tests can reportedly reduce the risk of side effects<ref>Bridges, S. (2006). The promise of chelation. Mothering , 54-61.</ref>.

Because of the lack of empirical support in controlled studies and the possibility of dangerous side effects, chelation therapy for the treatment of autism is not recommended. The most effective known interventions for children with autism are educational and behavioral therapies.

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