St. John's Wort and Depression Research
by Cathy Wong, N.D., About.com

St. John's Wort is a medicinal herb that has been used for centuries to treat depression. Its use for mild to moderate depression has been supported by clinical studies in recent years, although unanswered questions remain concerning its effectiveness, how it works in the body and the long term effects.

Nevertheless, St. John's Wort has become the second most popular herb in the United States, with annual sales exceeding $104,000 million dollars.

A study published in a recent issue of the Journal of the American Medical Association (JAMA) has raised doubt about the effectiveness of St. John's Wort.

Conducted between November 1998 and January 2000 at 11 academic medical centers in the United States, the study compared St. John's Wort to a placebo for the treatment of major depression.

The researchers addressed many of the methodological flaws of previous studies by using a heterogenous group of patients all clinically diagnosed with major depression. They also used a standard measure for rating symptoms of depression, a longer treatment duration of eight weeks, a larger sample of patients and a placebo group.

The 200 subjects in the study were randomly divided into two groups. One group received a 300 mg tablet extract of St. John's Wort and the other group received an identically matched placebo for an eight week treatment period. Both groups were instructed to take one tablet three times per day.

After four weeks, the dosage of St. John's Wort or placebo was increased to 4 tablets per day for the remainder of the study if the subject had not shown improvement. The researchers concluded that St. John's Wort was not effective for the treatment of major depression.

It [may be] too soon, however, to throw in the towel on St. John's Wort for major depression.

This is one of the first studies examining the use of St. John's Wort for major depression. A daily dosage of 900-1200 mg was used. Since 900 mg/day is considered the effective dose for mild to moderate depression, the effective dose for severe depression may be greater than the 900-1200 mg/day used in this study. It is possible that the subjects receiving St. John's Wort may have significantly improved if they had been given the correct dosage.

Another point of question is that the St. John's Wort extracts used in this study were standardized to an ingredient called hypericin. The process of standardization is for quality assurance. It is a guarantee that a specified amount of an ingredient (presumably the medicinally active ingredient) is present in the herbal extract. The PDR for Herbal Medicine, a respected herbal reference, states that hyperforin and not hypericin may be the primary active ingredient for treating depression.

In one study, patients received either placebo, a St. John's Wort extract standardized to 0.5% hyperforin, or a St. John's Wort extract standardized to 5% hyperforin. Only patients who received the extract of 5% hyperforin showed significant improvement of depressive symptoms (Laakman et al.). It is possible that in the JAMA study, the subjects receiving the St. John's Wort extract may have significantly improved if the extract had been standardized to hyperforin.

The researchers rightly conclude that more methodologically rigorous studies of St. John's Wort for severe depression are needed. Until then, it may be prudent to limit its use to mild to moderate depression under the careful supervision of an appropriately trained health practitioner.

References
1. Blumental M, Goldberg A, Brinckman J. Herbal Medicine Expanded Commission E Monographs. American Botanical Council with Integrative Medicine Communications First Edition. Newton, MA 2000.
2. Drug Store News, May 2000.
3. Physician’s Desk Reference (PDR) for Herbal Medicines (2nd ed.). New Jersey: Medical Economics Company, Inc. 2000; 488-489.
4. Murray M, Pizzorno J. Textbook of Natural Medicine Vol.1 and 2. Edinburgh: Harcourt Publishers, 1999.
5. Shelton RC, Keller, MB, Gelenberg A, Dunner DL, et al. Effectiveness of St. John's Wort in major depression. JAMA. 2001;285:1978-1986.

PsychLinks Comment: Note that St. John's Wort is not free of side-effects and is known to interact adversely with several prescribed medications as well as to increase sensitivity to sunlight. If you are thinking of trying this alternative medication, please make sure that you first consult with your physician. -- David Baxter