Ferrier estimated that 1.5 million Americans are regular users of St. John's wort and an additional 3 million to 4 million have tried it in recent years. Like other dietary supplements, the herbal extract is available without prescription in many stores and is not subjected to the clinical testing standards applied to drugs. Dr. Janette Gray, an internal medicine specialist in Bay Park, said she suggests St. John's wort to many of her patients. An estimated 5 percent of the U.S. population has major depression, and only half of them or fewer are believed to be getting medical treatment, Stahl said. Major depression includes a consistent pattern of symptoms such as feelings of helplessness or being worthless, lack of motivation and energy, lack of pleasure in normal activities, sleeplessness, weight loss, agitation and thinking problems.
Psychiatrists diagnose the disease with a series of standardized questions.
The 200 participants in the study published today were categorized as having moderate or severe major depression. Half of them took St. John's wort extract and half a placebo, and no one knew which they received. After eight weeks, interviews using the same diagnostic questions showed no significant improvement, on average, for either group.