Oct. 10, 2008 -- Can taking an herbal supplement be as good as a prescription medication for people who are depressed?
Researchers in Germany think so.
A team working for a firm that makes St. John's wort extract has found that taking high-quality St. John's wort can be as effective as standard prescribed antidepressants for some depressed people.
The study authors disclose that they were paid speaking and travel fees by the German company Schwabe, which produces St. John's wort extract.
St. John's Wort and Major Depression
The researchers reviewed 29 trials of St. John's wort involving 5,489 people.
The trials included adults with major depression who were randomly assigned either St. John's wort, a placebo, or a standard prescription antidepressant. Neither the participants nor the researchers knew who was getting which treatment during the trials.
Reviewers found that in nine of the larger trials, people who took St. John's wort and those who took a standard antidepressant for four to 12 weeks had similar outcomes when it came to how well they felt after treatment.
The reviewers also concluded that St. John's wort was more effective than placebo and had fewer side effects than standard antidepressants.
People who took St. John's wort tended to drop out of trials less often because of side effects than those who were taking an older class of antidepressants.
"Compared to 2005, the evidence that [St. John's wort] extracts are effective is better now," says study researcher Klaus Linde, with the Centre for Complementary Medicine Research at Technical University in Munich, Germany, in a news release.
Charles Raison, MD, who is with the department of psychiatry and behavioral sciences at Emory University's School of Medicine, agrees. Raison was not involved in the study.
Raison says there is enough evidence now to suggest that St. John's wort has "at least a fifty-fifty chance of having antidepressant effects."
Would he advise patients to take it?
"I don't know," says Raison. He'd prefer to use traditional antidepressants as a first line of treatment for severe depression.
But if a patient insisted on trying it, Raison says he might "give it a whirl" if it's appropriate for the patient. St. John's wort can interact with other medications in the blood and can make them less effective.
Raison notes that an important thing he's learned from medical training is "anything that has good effects, also has side effects."
Quality of St. John's Wort Varies
Scientists are still not sure how St. John's wort works for depression. The authors of this study write that at least seven ingredients may be involved.
According to the researchers, studies from German-speaking countries appear to have better results from taking St. John's wort for depression. They note that St. John's wort has a long tradition of use in these countries, and the "difference could be due to the inclusion of patients with slightly different types of depression, but it cannot be ruled out that some smaller studies from German-speaking countries were flawed and reported over-optimistic results."
The authors write that the quality of St. John's wort "can differ considerably."
They note that a recent study of what is available on German store shelves found that a number of brands contain only a tiny amount of the main active ingredients thought to be key for treating depression.
Power of Placebo
Linde says in a news release that those products with very low concentrations may only work by a placebo effect.
Raison says a placebo can be a "very powerful antidepressant."
"There's a whole body of literature now that shows placebo can have a direct effect on the pathways of the brain and work like an antidepressant."
Timing of Antidepressants
How long do traditional antidepressants take to kick in?
The old thinking was that you wanted to see depression lift within four to six weeks, but Raison says that is changing. "You want to see within a week or two that patients are getting better."
According to Raison, one reason is that the "longer it takes [a traditional antidepressant] to work, the more vulnerable people are to have a relapse."
The review and findings are published in The Cochrane Library.