Study Questions St. John's Wort Effectiveness in Treating Severe Depression

Millions of Americans have used the herbal supplement St. John's wort to treat depression. Now a new study raises questions about its effectiveness. Our health correspondent Dr. Emily Senay explains.

It's become one of the biggest herbal sellers on the market since it hit the alternative scene in a big way several years ago. St. John's wort, also known as Hypericum perforatum, is a flowering plant said to help with symptoms of depression without some of the side effects associated with prescription antidepressants. Past studies demonstrating the herb's effectiveness have been conflicting and controversial.

The Journal of the American Medical Association reports in the latest and perhaps most thorough study of St. John's wort that there is currently no credible evidence to support its effectiveness for people with severe depression.

Does this mean St. John's wort does not work in treating depression?

This is not the final answer for St. John's wort as a treatment for depression. Experts on all sides of the issue agree that the question of whether or not it really works will be definitively answered by a large study going on at the National Institutes of Health that will hopefully be out within the next year.

Other studies have supported the use of St. John's wort. How was this study conducted and why is it different from the others?

For 8 weeks half of the people who had major depression in this double-blinded study got St. John's wort extract; the other half got a dummy pill--a placebo. There was no difference between the two groups as far as improvement in symptoms of depression.

The study raises serious questions that are being debated back and forth between experts. Criticisms of this latest study include the possibility that the group of study patients were what are known as nonresponders--that is, no treatment works for them and therefore the results were destined to be negative. This morning's study received funding from several sources, including Pfizer, a maker of prescription antidepressants.

Since it received funding from Pfizer does that mean the results of the study are tainted?

No. But critics will say this. Many studies receive pharmaceutical funding and it is important to know this.

What about all those people who say St. John's wort worked for them?

What this study did not look at were people who were actually seeking an alternative treatment and people who had more or less serious types of depression, not the type looked at in this study. Therefore, we don't know about these people. It is entirely possible--and the authors note this--that these types of people may indeed experience a response to St. John's wort. And certainly there have been other studies, many European, which found benefit for those people who do not have depression but rather doctors' name for "the blues"--dysthymia. But this morning's study is the most rigorous scientifically so far.

How do you dtermine if you have "the blues" or if you are depressed?

Symptoms of depression include

Trouble sleeping.

Change in appetite (eat too much or too little).

Trouble with memory.

Feelings of hopelessness, worthlessness, guilt, or shame.

Thoughts of death or suicide.

What if you feel depressed and are taking St. John's wort or thinking about taking St. Johns wort?

If you have significant symptoms of depression the experts I spoke with on both sides agree that the first step is to see a doctor. Self-medicating is not recommended because depression is associated with illness and even suicide. The authors of this study are firm in stating that until we know more about St. John's wort, it should not be used in people with significant depression. It is important to note that many people receive no treatment for depression and never seek medical assistance.

About the Study

According to the results of a new study published in the <em>Journal of the American Medical Association</em>, the herb St. Jhn's wort should not be used to treat patients with major depression.

In recent years extracts of the over-the-counter herb have been widely used to treat mild-to-moderate depression. But questions remained as to its effectiveness in treating major depression.

One of the authors of this latest study now says there are serious questions about the effectiveness of the herbal remedy in treating moderate-to-major depression. The small flowering weed has been used for more than 2,000 years to treat a variety of "nervous conditions" including perimenopause, PMS, and nocturnal bed wetting in children.

More than two dozen clinical trials have been conducted with St. John's wort. Most have significant flaws in design and do not enable meaningful interpretation, according to JAMA.

The study conducted by Vanderbuilt University between November 1998 and January 2000 examined 200 adult outpatients diagnosed to have major depression. Some of them were given placebo and others St. John's Wort for 8 weeks. The extract of St. John's wort failed to produce significant difference compared to placebo on any of the outcome measures used. The results of the study suggest that persons with significant major depression should not be treated with St. John's wort given the mortality risks of untreated or ineffectively treated major depression.

This is the first significant American study on St. John's wort and major depression. Europeans have been using St. John's wort as a part of their medical practice for close to 20 years.

More from CBS News