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Review Questions Effectiveness of St. Johns Wort for Symptoms of Major Depression

A new study of clinical trials involving nearly five thousand patients has reaffirmed that St. John’s Wort reduces symptoms of depression among adults suffering mild to moderate symptoms but questions the herbal extract’s effectiveness for moderate to severe depression. The study also indicates that serious drug interactions can occur between St. John’s Wort and other frequently used anti-depressants.

Hypericum extract, or St. John’s Wort, available over the counter in the United States and United Kingdom and by prescription in many European countries, has found widespread popularity as a relatively inexpensive, natural anti-depressant. A recent review of 37 separate studies involving nearly 5000 patients has reaffirmed earlier findings that St. John’s Wort:

  • Reduces symptoms of mild-to-moderate depression among adults in a manner similar to antidepressant drugs;
  • Causes fewer side effects than some of the older antidepressants on the market; and
  • Causes slightly fewer side effects compared with selective serotonin reuptake inhibitors, or SSRIs, the class of antidepressants most recently developed.

However, the report also cautions that “uncontrolled use of [St. John’s Wort] is problematic because serious interactions can occur” and indicates that the herbal extract is less effective for major depression. The review also recommends caution with regard to the variability in quality of commercial hypericum extracts. From a press release from the Center for the Advancement of Health:

Hypericum extracts are decidedly less expensive than some of the most widely prescribed antidepressants, such as Prozac. However, the composition of St. John’s Wort depends on the raw plant material used, the extraction process and the solvents used. As a consequence, the review notes, “the amounts of bioactive constituents in different products can vary enormously.”

Reviewers recommend that St. John’s Wort products should be avoided if they do not provide important content information, such as the amount of total extract contained, the extraction fluid used and the ratio of raw material to extract. They also call for more detailed studies of the constituent components of St. John’s Wort.

Dr. John Williams, a professor of medicine and psychiatry at Duke University who has studied St. John’s Wort in the context of depressed patients in primary care facilities, says the Linde review has made him more cautious in his outlook on the product. Williams says he currently feels St. John’s Wort should not be “a first or second choice for U.S. patients with moderate to severe major depression.” At the same time, he says, the product remains a “reasonable option” for patients suffering from minor depression — as long as they are able to locate “quality preparations.”

The study was published by the Cochrane Collaboration, an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions.