by Chris O'Brien
A Cochrane review of 29 trials involving 5,489 patients found St. John's Wort superior to placebo in patients with major depression and "similarly as effective as other antidepressants," but with fewer side effects. The review, which included 18 studies comparing the hypericum extract to placebo and 17 studies comparing the extract to other synthetic antidepressants, focused on double-blind and randomized trials on adults with major depression.
Several years ago, two American studies published in JAMA found St. John's Wort to be ineffective at treating major depression.
"These [JAMA-published] studies are included in the meta-analysis," said study lead Klaus Linde, M.D., from the Center for Complementary Medicine in Munich, Germany. "Also, in the area of standard [synthetic] antidepressants, one in three trials finds no difference versus placebo, so negative results are not uncommon. Taking all the available trials together, however, the evidence has been and still is in favor of the hypothesis that the tested hypericum extracts are effective."
The study said that depressive disorders, characterized by depressed mood and/or loss of interest or pleasure in nearly all activities, are the largest source of non-fatal disease burden in the world, accounting for 12 percent of human years lived with a disability.
Depressive disorders affect 121 million people worldwide, according to the World Health Organization, and are often accompanied by other symptoms including loss of appetite, fatigue and lack of energy, sleep disturbance, restlessness or irritability, feelings of worthlessness or inappropriate guilt, difficulty in thinking, concentrating or making decisions and thoughts of death or suicide or attempts at suicide.
The review said that broader studies with more subjects tend to produce less favorable results, whereas smaller, specific studies, such as those in Germany where the herbal extract is prescribed by physicians for depression, show more favorable results. In Germany, adequately dosed hypericum extracts are licensed as drugs, not as supplements.
"The studies do not take into account lifestyle considerations, but investigate hypericum extracts as one would a drug," Linde said. "The daily extract dose should be between 500 and 1200 mg, but the quality and composition of extracts can vary."
The study said that patients suffering from depressive symptoms who wish to use a St. John's Wort product should consult a health professional. Because St. John's Wort products may vary greatly, the results of this review apply only to the preparations tested in the studies included, and possibly to extracts with similar characteristics.