A controversial treatment for autism spectrum disorder (ASD) is not only ineffective but may be harmful, according to a study conducted by Baylor University researchers.
The treatment, known as chelation, attempts to eliminate metals such as mercury from the body.
"The chemical substances used in chelation treatment have a myriad of potentially serious side effects such as fever, vomiting, hypertension, hypotension, cardiac arrhythmias and hypocalcemia, which can cause cardiac arrest," said Tonya N. Davis, Ph.D., assistant professor of educational psychology in Baylor's School of Education and co-author of the study. To view the study, published in Research in Autism Spectrum Disorders, visit http://www.sciencedirect.com/science/article/pii/S1750946712000724.
In one example mentioned in the research, "a 5-year-old with ASD died from cardiac arrest caused by hypocalcemia while receiving intravenous chelation." And, a 2008 clinical study of chelation treatment for autism was suspended due to potential safety risks associated with chelation.
"Chelation therapy represents the 'cart before the horse' scenario where the hypothesis supporting the use of chelation was not validated prior to using it as a form of treatment. Evidence does not support the hypothesis that ASD symptoms are associated with specific levels of metals in the body," said Davis, supervisor of the Applied Behavior Analysis Program at the Baylor Autism Resource Center.
In the study, Davis and colleagues reviewed the research findings of five published studies on chelation. In the studies, 82 participants ages 3 to 14 received chelation treatment ranging from one to seven months.
Of the five studies, four showed mixed results-some positive and negative outcomes for each of the study participants-and one study showed all positive results. But after closer review, Davis and her research team found "methodological weaknesses" in the studies.
"Several studies used numerous treatments at once in addition to chelation that made it impossible to determine if the positive results could be attributed to chelation alone," Davis said.
Ultimately, Davis found that the research studies did not support the use of chelation as some have claimed and were "insufficient, which is the lowest level of certainty."