1. What is St. John's wort?
St. John's wort (Hypericum perforatum in Latin) is a long-living plant with yellow flowers. It contains many chemical compounds. Some are believed to be the active ingredients that produce the herb's effects, including the compounds hypericin and hyperforin.
How these compounds actually work in the body is not yet known, but several theories have been suggested. Preliminary studies suggest that St. John's wort might work by preventing nerve cells in the brain from reabsorbing the chemical messenger serotonin, or by reducing levels of a protein involved in the body's immune system functioning.
2. 2. For what medicinal purposes has St. John's wort been used?
St. John's wort has been used for centuries to treat mental disorders as well as nerve pain. In ancient times, doctors and herbalists (specialists in herbs) wrote about its use as a sedative and treatment for malaria as well as a balm for wounds, burns, and insect bites. Today, St. John's wort is used by some people to treat mild to moderate depression, anxiety, or sleep disorders.
3. Why is St. John's wort used as an alternative treatment for depression?
Some patients who take antidepressant drugs do not experience relief from their depression. Other patients have reported unpleasant side effects from their prescription medication, such as a dry mouth, nausea, headache, or effects on sexual function or sleep.
Sometimes people turn to herbal preparations like St. John's wort because they believe "natural" products are better for them than prescription medications, or that natural products are always safe. Neither of these statements is true (this is discussed further below).
Finally, cost can be a reason. St. John's wort costs less than many antidepressant medications, and it is sold without a prescription (over the counter).
4. How widely is St. John's wort used for treating depression?
In Europe, St. John's wort is widely prescribed for depression. In the United States, St. John's wort is not a prescription medication, but there is considerable public interest in it. St. John's wort remains among the top-selling herbal products in the United States.
5. How is St. John's wort sold?
St. John's wort products are sold in the following forms:
- Capsules
- Teas--the dried herb is added to boiling water and steeped for a period of time.
- Extracts--specific types of chemicals are removed from the herb, leaving the desired chemicals in a concentrated form.
6. Does St. John's wort work as a treatment for depression?
There has been scientific research to try to answer this question.
In Europe, results from a number of scientific studies have supported the effectiveness of certain St. John's wort extracts for depression. An overview of 23 clinical studies found that the herb might be useful in cases of mild to moderate depression. The studies, which included 1,757 outpatients, reported that St. John's wort was more effective than a placebo (here, a "dummy" pill designed to have no effect) and appeared to produce fewer side effects than some standard antidepressants (Linde et al. British Medical Journal, 1996).
Other studies conducted recently have found no benefit from the use of St. John's wort for certain types of depression. For example, the results of a study funded by Pfizer Inc., a pharmaceutical company, found that St. John's wort, when compared with placebo, was not effective for treating major depression (Shelton et al. JAMA, 2001).
In addition, several components of the National Institutes of Health (NIH)--NCCAM, the Office of Dietary Supplements (ODS), and the National Institute of Mental Health (NIMH)--funded a large, carefully designed research study to find out whether St. John's wort extract benefits people with major depression of moderate severity. This clinical trial (a research study in people) found that St. John's wort was no more effective for treating major depression of moderate severity than placebo (Hypericum Depression Trial Study Group. JAMA, 2002; for further information, view the press release online at nccam.nih.gov/news/2002 or contact the NCCAM Clearinghouse).
7. Are there any risks to taking St. John's wort for depression?
Yes, there are risks in taking St. John's wort for depression.
Many so-called "natural" substances can have harmful effects--especially if they are taken in too large a quantity or if they interact with something else the person is taking.
Research from NIH has shown that St. John's wort interacts with some drugs--including certain drugs used to control HIV infection (such as indinavir). Other research shows that St. John's wort can interact with chemotherapeutic, or anticancer, drugs (such as irinotecan). The herb may also interact with drugs that help prevent the body from rejecting transplanted organs (such as cyclosporine). Using St. John's wort limits these drugs' effectiveness.
Also, St. John's wort is not a proven therapy for depression. If depression is not adequately treated, it can become severe and, in some cases, may be associated with suicide. Consult a health care practitioner if you or someone you care about may be experiencing depression.
People can experience side effects from taking St. John's wort. The most common side effects include dry mouth, dizziness, diarrhea, nausea, increased sensitivity to sunlight, and fatigue.
8. What are some other possible problems with using St. John's wort?
Herbal products such as St. John's wort are classified as dietary supplements by the U.S. Food and Drug Administration (FDA), a regulatory agency of the Federal Government.
The strength and quality of herbal products are often unpredictable. Products can differ in content not only from brand to brand, but from batch to batch. Information on labels may be misleading or inaccurate. For more information on safety issues, see the NCCAM fact sheet "Herbal Supplements: Consider Safety, Too."
9. Is NCCAM funding research on St. John's wort, including for depression and other mental illnesses?
Yes. For example, recent projects supported by NCCAM include:
Safety and effectiveness of St. John's wort for the treatment of minor depression
Safety of St. John's wort for the treatment of social phobia
Effectiveness of St. John's wort for the treatment of obsessive compulsive disorder
Effects of St. John's wort on how well birth control pills work
Possible adverse interactions of St. John's wort and narcotic pain medications
National Center for Complimentary and Alternative Medicine
