TUESDAY, June 10 (HealthDay News) -- St. John's wort isn't effective for treating attention-deficit hyperactivity disorder (ADHD) in children, a new study finds.
Published in the June 11 issue of the Journal of the American Medical Association, the study compared St. John's wort to a placebo in children aged 6 to 17 and found the herb wasn't any more effective than the placebo.
"To my knowledge, this is the first placebo-controlled study of St. John's wort for ADHD. We believed that some parents were using it to treat their children, and there was a potentially plausible biological mechanism, so we went into the study not knowing what we were going to find," said study author Wendy Weber, a research associate professor in the School of Naturopathic Medicine at Bastyr University in Kenmore, Wash.
But, said Weber, "in our study, a pretty standard dose of St. John's wort didn't provide benefit."
She added that most herbal supplements, and especially St. John's wort, have the potential to interact with other medications, which is why it's important to consult your child's doctor before trying anything new. In the case of St. John's wort, said Weber, it increases the metabolism of other drugs.
Previous studies of St. John's wort in children with depression have had mixed results, according to the study. The herb has been found to affect the metabolism of the brain chemicals serotonin, norepinephrine and dopamine. A medication (buproprion hydrochloride) sometimes used to treat ADHD, though not FDA-approved for that purpose, acts in a similar manner on these chemicals.
Because there appeared to be a potential biological explanation for the use of St. John's wort in ADHD, and because the authors suspected that parents were already using the drug for that purpose, they designed a small randomized, double-blind placebo-controlled trial of St. John's wort.
Fifty-four children between the ages of 6 and 17 who met the diagnostic criteria for ADHD were recruited for the study. During the first week, all of the children were given a placebo, and none were allowed to take ADHD medications. Those who had been taking prescription medications underwent a "washout" period before the start of the study to make sure they had no medication left in their bodies.
