St. John's wort is no better than a placebo for ADHD, Bastyr study finds

St. John's wort works no better than a dummy pill in treating attention-deficit/hyperactivity disorder (ADHD) in children, according to a new study by Seattle-area researchers.

Though it was a small trial, the findings dampen hope for a leading herbal alternative to the potentially dangerous stimulants that are typically prescribed for the condition.

In the study, led by Bastyr University in Kenmore, 54 Seattle-area children, ages 6 to 17, were randomly given either rice protein placebo pills or St. John's wort for eight weeks. All the children showed only very mild improvements in hyperactivity and inattentiveness.

In fact, the dummy-pill group reported slightly better results, although that could have been just chance.

The findings were published Tuesday in the respected Journal of the American Medical Association. The trial was the first to pit St. John's wort against a placebo in children and adolescents with attention disorders.

St. John's wort, once hailed as "nature's Prozac," has been shown in clinical trials to help mild or moderate, but not major, depression. The plant's compounds are thought to increase levels of brain chemicals that help lessen depression, anxiety and inattention.

Researchers theorized that St. John's wort might temper the symptoms of ADHD as well. It did not.

"We saw no treatment benefit at all from St. John's wort," said Wendy Weber, a naturopathic doctor at Bastyr and the study's lead author. Researchers from Children's Hospital and Regional Medical Center and the University of Washington were among those involved.

As many as 4 million American adults and children take stimulants to treat attention disorders, including 10 percent of 10-year-old boys, according to federal estimates. But in 2006, the Food and Drug Administration ordered that ADHD drugs such as Adderall, Ritalin and Concerta be labeled with warnings because they can cause sudden death, heart attacks and hallucinations.

Perhaps as a reaction to those potential dangers, a small but growing number of people are switching to or supplementing conventional medicine with botanical therapies. In addition to St. John's wort, parents have reported giving their children ginkgo biloba, echinacea, ginseng and other herbal compounds for hyperactivity or depression.

A decade ago, St. John's wort was America's second-best-selling herbal supplement, outselling all but ginkgo. But since then, two large studies have found that it's no more effective than a placebo against moderately severe clinical depression. By 2007, St. John's wort sales had fallen by 75 percent to $56 million, according to Nutrition Business Journal. St. John's wort is sold as a prescription anti-depressant in Germany and parts of Europe.

Despite the latest negative finding, Weber said it's not enough to rule out St. John's wort as a potential therapy for hyperactivity and attention problems. For one thing, the children in Weber's study took 300 mg of St. John's wort three times daily; it's possible that a larger dose is needed. For another, it's unclear whether it's hypericin or hyperforin, the key active agents in St. John's wort, that may be the crucial player against ADHD.

Nonetheless, Dr. P. Murali Doraiswamy, chief of biological psychiatry at Duke University, called the study "a wake-up call" to stop treating children with untested remedies.

"Dozens of unproven cocktails, many with St. John's wort, are being sold on the Internet with claims to be able to help attention and hyperactivity," Doraiswamy said. "Ninety-nine percent of herbals are still unproven."

St. John's wort interferes with about half of all drugs, mainly by flushing them out of the body more quickly and thus reducing their effectiveness. A 90-capsule bottle of Vital Nutrients brand St. John's wort used in the study sells for $15 to $19.

Doraiswamy contends that while many herbs likely have valuable medicinal properties, much of it has yet to undergo rigorous scientific testing. Claims for popular remedies such as echinacea to prevent colds and ginkgo to improve memory have failed to hold up in large clinical trials.

But Mark Blumenthal, executive director of the American Botanical Council, said that many of the best-selling herbal supplements are backed by research as well as thousands of years of human use.

Blumenthal, whose nonprofit group promotes accurate information on botanical medicine, contends that there is a strong link between a product's popularity and its clinical evidence. People take black cohosh for menopausal symptoms or garlic to reduce plaque buildup in arteries because they work, he said. (One randomized trial on black cohosh, reported by Seattle's Group Health Cooperative in 2006, found that it did not relieve hot flashes in older women.)

"It's not just consumer faith," Blumenthal said.

Kyung Song: 206-464-2423 or ksong@seattletimes.com