St. John's Wort

Claims, Benefits: Alleviates depression.

Bottom Line: It may help against mild forms of depression. But think twice before taking it. Certainly, talk to your doctor or therapist before taking it, especially if you take any prescription medication. It's hard to draw the line between moderate and severe depression.

Full Article, Wellness Letter, August 2001:

Another Look at St. John's Wort and Depression

Books, articles, and word of mouth have made St. John's wort famous as a do-it-yourself antidepressant. The yellow flowers of this weed (Latin name, Hypericum perforatum) have for centuries been used as a treatment for anxiety, "nervous disorders," and insomnia, as well as many other problems. This herbal remedy has long—and widely—been used as an antidepressant in Germany, where it is usually sold by prescription. Unlike most herbal products, St. John's wort has been extensively studied. The evidence has remained shaky, however. A new study makes St. John's wort look even iffier.

Published in the Journal of the American Medical Association in April, the large well-designed study compared the herb to a placebo in 200 people with severe depression over an eight-week period. The herb didn't do significantly better than the placebo. The main side effect was headaches.

The new study focused on people who had been severely depressed for at least two years. Previous studies suggested that St. John's wort works better than a placebo, and sometimes as well as antidepressant drugs, for mild to moderate forms of depression. But most of these earlier studies were small, poorly designed, or otherwise flawed. There has never been any evidence that the herb can help against major depression, and it has not been recommended for this purpose. Another large study on St. John's wort, sponsored by the National Institutes of Health, may help clarify things, particularly since it will last longer and will compare the herb to a prescription antidepressant. Results are expected at the end of the year.

At least it's safe—or is it?

Many people are attracted to St. John's wort (like other herbs) because it is supposed to be safe. Minor side effects, such as headaches, gastrointestinal discomfort, sun sensitivity, and dry mouth, are common. In contrast, more than half the people taking prescription antidepressant drugs (even the newer ones like Prozac or Zoloft) experience side effects, sometimes severe ones.

But herbs can have unintended effects. With the increasing use of St. John's wort have come more and more reports of serious adverse effects. This herb contains at least 10 compounds that can have pharmacological action. Some of these are known to affect the way the liver metabolizes drugs, which can result in blood levels of these drugs that are too high or too low. But the interactions are largely unpredictable for several reasons—the amounts of the active compounds in the supplements can vary widely, people take a wide range of dosages, and the potency indicated on the labels is often inaccurate (according to laboratory analyses) and measures only one compound.

Recent research, for instance, has revealed potentially hazardous interactions between St. John's wort and many medications, leading the FDA to issue a warning about the herb. Many people with HIV try St. John's wort, for instance, but it's now known that the herb can dangerously reduce blood levels of important HIV drugs (protease inhibitors and possibly others). It also interacts with the blood thinner warfarin (brand name Coumadin), the heart drug digoxin, cyclosporin (which helps prevent transplant rejection), and some oral contraceptives. In addition, the herb can intensify or prolong the effect of some anesthetic agents. So, if you take St. John's wort and are going to receive anesthesia, make sure your anesthesiologist knows. This herb can also cause dizziness, confusion, headaches, and anxiety when combined with conventional antidepressants, especially in older people.

Not the last word: Think twice before taking St. John's wort. Certainly, talk to your doctor or therapist before taking it, especially if you take any prescription medication. If you're depressed, don't make your own diagnosis—it's hard to draw the line between moderate and severe depression. If you're taking a conventional antidepressant, don't switch to the herb on your own, and don't combine the two. If you have HIV and are taking medication for it, do not take St. John's wort.

For information about depression, go to the website of the National Institute of Mental Health. You can also get free brochures about de-pression or anxiety disorders by calling the Institute toll-free at 800-421-4211.

UC Berkeley Wellness Letter, August 2001