What causes the frequently diagnosed behavioral problem in children known as attention deficit and hyperactivity disorder (ADHD) that leads to countless youngsters being given side-effect laden stimulant drugs? Research has focused on genes and, more recently, on the idea that multiple environmental triggers could be the cause. For example, according to the National Institutes of Health (NIH), a recent British study indicates that certain food additives like artificial colors or preservatives could cause
ADHD symptoms in some children.
Now two studies -- one
published in the January issue of the
Journal of Child Psychology and Psychiatry and the other published in the February issue of the journal
Current Directions in Psychological Science -- provide the best evidence yet that lead could be one of the biggest culprits behind ADHD.
At very high levels, lead poisoning can cause seizures, coma, and even kill. But it is chronic, long term exposure that is the more common health threat, especially for children. Researchers have previously linked elevated blood levels of lead in kids to problems ranging from mental retardation to learning disabilities. In a statement the media, Oregon Health and Science University researcher Joel Nigg, who co-authored both of the new studies, pointed out that almost all Americans have a low-level exposure to lead, a well-known neurotoxin, making the metal an ideal candidate for causing ADHD.
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