Also in Slate: Sydney Spiesel explains why parents believe in autism cures that don't work.
One of the more popular tests, in recent years, has been for traces of toxic metals. The testing methodology is explained here. In a nutshell, Doctor's Data classifies the level of mercury in the urine of a recently chelated child by comparing it with base-line levels in normal, unchelated children. Naturally, the chelated levels are higher. That's what chelators do: They leach metals out of tissue. Plus, everyone has a little bit of mercury in them, because trace amounts are in our air, water, and food. What's remarkable is that so many people have relied on the data from these tests.
In July 2000, in preparation for heavy-metals testing, Colten was administered 100 milligrams of the chelating agent DMSA. When Doctor's Data tested his urine, it found 2.2 micrograms of mercury per liter. Even though 2.2 micrograms is about what you'd find in the urine of a normal, nonchelated person, Doctor's Data reported the result as "very elevated." And although conventionally trained pediatricians are instructed not to use chelation even for acute lead poisoning—unless the level is above 70 micrograms per liter of urine—Bradstreet, who is not trained in pediatrics or neurology, decided to chelate Colten, as he does with about one-third of his patients.
Among the parents and physicians of Defeat Autism Now!, it is an article of faith that these children are genetically vulnerable to damage from "toxins" like thimerosal. There's little scientific evidence to support that belief. Indeed, Vowell found "no reliable evidence" of hypersusceptibility to mercury in children with autism diagnoses.
But many parents remain convinced that chelation helped. "I think we're in a strange world when judges are opining on treatments for autism," said J.B. Handley, co-founder of Generation Rescue, a group that attributes many cases of autism to vaccines. "We hear more reports from parents than ever that chelation is working." In an e-mail message, Handley hypothesized that even if thimerosal were not solely to blame for autism, chelation still had beneficial effects. "We don't have answers for everything, and more kids are recovering."
To me, the Doctor's Data tests look like an artifact of science being put to unscientific use. A parent in search of answers on how to improve the health and communication skills of a profoundly disabled child isn't likely to focus on the finer points of matched controls. "Someone waves this sheet in front of you and says, 'You're three times the background rate!' " says Dr. Robert Baratz, a cell biologist and internist in Braintree, Mass., who has testified on chelation before medical boards. "Their agenda is to make money off of somebody else's misfortune. When you look at their charts, they never cure any patients. It's merely a matter of how close you can get to the bottom of their wallet."
Then comes the bully pulpit, the advocacy groups, doctors, and supplement salesmen who claim that chelation cures children. They overlook the fact that most kids' behavior will change as they grow older, whether or not they are autistic. To attribute these changes to an implausible treatment, without a controlled study, is wishful thinking.
Science hasn't figured out how to deal with autism, because the neural changes that probably cause it occur in the womb and it's a condition defined by behavior, not biological markers. In the absence of satisfactory answers, good money chases bad.
Doctor's Data did not respond to a request for an interview. An individual close to the company said there was no way to establish a base line for post-chelation samples, which might have been provoked by any number of different chelating agents, at varying doses. "The tests are ordered by physicians, so they can interpret the results," this person said. "They do what they want with this information." But copies of the reports, which chart the child's mercury levels into deceptively shaded "elevated" and "very elevated" areas, are typically provided to both physicians and patients.
Bradstreet eventually realized that chelation wasn't working for Colten. After conducting a painful spinal tap and a gut biopsy, he concluded that Colten was suffering not so much from thimerosal as from the effects of the measles-mumps-rubella shot, which contains no mercury. He began administering regular intravenous immune globulin, conventionally given to immunocompromised patients. The family said Colten improved on this therapy—at $3,000 a pop, though, they often couldn't afford it.