A study with 54 children and adolescents with Attention Deficit Hyperactivity Disorder (ADHD) found no significant effects on supplements of St. John's wort ( Hypericum perforatum ), according to researchers from Bastyr University in Washington.
"To our knowledge, this is the first placebo-controlled trial of H perforatum in children and adolescents.
The results of this study suggest that administration of H perforatum has no additional benefit beyond that of placebo for treating symptoms of child and adolescent ADHD," wrote lead author Wendy Weber.
ADHD is thought to affect between three to seven per cent of children in the UK, with the problem continuing into adulthood for as many as 60 per cent of sufferers.
Boys are reported to be three times more likely than girls to suffer from ADHD, according to the National Attention Deficit Disorder Information and Support Service (ADDISS).
Established treatments include prescription drugs, such as Ritalin.
However, concerns about the drug have been raised from various quarters, including the British House of Lords.
Prescriptions for the drug, chemical name methylphenidate, are reported to have increased from 2,000 in 1991 to over 300,000 in 2005.
"For these reasons, many parents seek complementary or alternative medicine for their children with ADHD," wrote Weber.
"Complementary or alternative medicine treatments used for paediatric ADHD include massage, dietary changes, dietary supplements, and herbal treatments.
In the United States, the most common herbal treatments used by children with ADHD are St John's wort, Echinacea species, and Ginkgo biloba."
Study details Weber and co-workers recruited 54 children with ADHD aged between six and 17, and randomly assigned them to receive a daily supplement of 300 mg of H. perforatum standardised to 0.3 per cent hypericin (Vital Nutrients Inc, Connecticut) or placebo for eight weeks.
The participants were not allowed to take other ADHD medications during the trial.
At the end of the study, the researchers report no significant differences between the groups with respect to inattentiveness or hyperactivity.
Door is still open According to the comment section of the JAMA article, the authors do not close the door on the use of the herbal for ADHD.
Indeed, they state: " This trial was designed as a single agent clinical trial, so the results pertain only to the use of H perforatum in isolation for the treatment of ADHD.
It is possible that H perforatum may work synergistically with other botanicals, vitamins, minerals, or supplements."
Moreover, they state add that the hyperforin content may have been insufficient to produce any effects.
The compound is reported to play a role in inhibiting the reuptake of serotonin, dopamine, and norepinephrine, all of which play a role in mood.
"The product used for this study was not one of the newly marketed "high-hyperforin" products that range from three to five per cent hyperforin," wrote Weber.
"The product used in this trial was tested for hypericin and hyperforin content at the end of the trialandcontained only 0.13 per cent hypericin and 0.14 per cent hyperforin."
Weber also noted that the latter is very unstable and the rapid oxidation may have inactivated hyperforin in the product used in this clinical trial.
"It is possible that a product standardized to at least three per cent hyperforin could benefit children with ADHD symptoms if it were delivered in a method that limits oxidation," she added.
The researchers also note no difference in the adverse effects for either group was observed during the study.
The need for more study Based on the results of the current trial, the researchers concluded that H. perforatum was ineffective for ADHD in children.
"Nonetheless, if an H. perforatum product with stable and high hyperforin content became available for investigation, it would be worthwhile to conduct a study to determine whether a clinically meaningful benefit could be achieved," they said.
Source: Journal of the American Medical Association 11 June 2008, Volume 299, Issue 22, Pages 2633-2641 "Hypericum perforatum (St John's Wort) for Attention-Deficit/Hyperactivity Disorder in Children and Adolescents - A Randomized Controlled Trial" Authors: W. Weber, A. Vander Stoep, R.L. McCarty, N.S. Weiss, J. Biederman, J. McClellan