St. John's wort is a herb that has a long history of use as a natural remedy for depression. Recent studies suggest it's more effective than a placebo for mild-to-moderate depression and that it's just as effective as tricyclic antidepressants.
Research on St. John's wort for severe depression, however, hasn't been as promising. For example, a large study published in the Journal of the American Medical Association (JAMA) compared St. John's wort to a placebo for the treatment of major depression. It was conducted between November 1998 and January 2000 at 11 academic medical centers in the United States.
The researchers addressed many of the methodological flaws of previous studies by using a group of patients who were similar in many respects and were all clinically diagnosed with major depression. Compared to previous studies, they also used a standard measure for rating symptoms, 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 dose of St. John's Wort or placebo was increased to four 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.
There were some issues with this study. It was one of the first studies examining the use of St. John's wort for major depression. A daily dosage of 900 to 1200 mg was used. Since 900 mg per day is considered the effective dose for mild-to-moderate depression, the effective dose for severe depression may be greater than the 900 to 1200 mg per day dose used in this study.
Another possible issue with this study is that 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's 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 another 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.
The researchers rightly conclude that more methodologically rigorous studies of St. John's wort for severe depression are needed. Until then, it should not be used by people with severe depression unless under the strict supervision of a qualified medical professional.
Sources:Blumental M, Goldberg A, Brinckman J. Herbal Medicine Expanded Commission E Monographs. American Botanical Council with Integrative Medicine Communications First Edition. Newton, MA 2000.
Drug Store News, May 2000.
Physician’s Desk Reference (PDR) for Herbal Medicines (2nd ed.). New Jersey: Medical Economics Company, Inc. 2000; 488-489.
Murray M, Pizzorno J. Textbook of Natural Medicine Vol.1 and 2. Edinburgh: Harcourt Publishers, 1999.
Shelton RC, Keller, MB, Gelenberg A, Dunner DL, et al. Effectiveness of St. John's Wort in major depression. JAMA. 2001;285:1978-1986.
