St. John's Wort as Effective as Zoloft®

St. John's wort (SJW), a popular herbal remedy, is at least as effective as the prescription drug sertraline (Zoloft®) in the treatment of depression and causes fewer side effects, according to a new study published in Canadian Family Physician (2002;48:905–8). This report confirms dozens of other studies demonstrating SJW is an effective treatment for mild-to-moderate depression, and contradicts two controversial studies suggesting the herb is of little or no benefit.

In the new double-blind study, 87 men and women suffering from depression were recruited from the practices of family physicians or through advertisements. Participants were randomly assigned to receive SJW (standardized to contain 0.3% hypericin), in the amount of 300 mg three times per day, or 50 mg per day of sertraline. If the degree of improvement was not satisfactory after the first 4 weeks, participants were instructed to take twice as much SJW or sertraline for the remainder of the study.

After 12 weeks, the severity of depression had decreased by an average of 50.2% in the SJW group and by 41.6% in the sertraline group. Although the advantage of SJW over sertraline was not statistically significant, the results indicated that SJW is at least as effective as, and possibly more effective than, sertraline. In addition, significantly more adverse side effects occurred in the sertraline group than in the SJW group after 2 and 4 weeks of treatment.

Dozens of previous studies have shown that SJW can relieve mild-to-moderate depression, although whether it is useful for severe depression remains in doubt. According to some reports, the efficacy of SJW is similar to that of several commonly used prescription antidepressant medications.

Two well-publicized double-blind studies published in the Journal of the American Medical Association (JAMA) concluded that SJW is not an effective treatment for depression. However, each of these studies had potential flaws. In the first study, although the remission rate was significantly greater with SJW than with placebo, only 14.3% of those who received the herb went into remission, causing the authors of the report to question its efficacy. However, the 4.9% remission rate in the placebo group was far below the placebo response rate seen in other studies of depression. That finding suggests that many of the participants recruited for this study would have been unlikely to respond to any treatment.

In the second JAMA study, depressed patients were given one of three treatments: SJW, placebo, or sertraline. Although SJW was no more effective than the placebo, by many measures neither was sertraline. The relatively poor outcome with sertraline makes one wonder whether the design of the study, or the criteria used to select participants, may have somehow skewed the results to make SJW appear less effective than it really is.

Despite these two negative studies, the bulk of the scientific evidence indicates that SJW is a safe and effective treatment for mild-to-moderate depression.

Alan R. Gaby, MD, an expert in nutritional therapies, served as a member of the Ad-Hoc Advisory Panel of the National Institutes of Health Office of Alternative Medicine. He is the Medical Editor for Clinical Essentials Alert, is the author of Preventing and Reversing Osteoporosis (Prima, 1994), and co-author of The Natural Pharmacy, 2nd Edition (Healthnotes, Prima, 1999), the A–Z Guide to Drug-Herb-Vitamin Interactions (Healthnotes, Prima, 1999), Clinical Essentials Volume 1 and 2 (Healthnotes, 2000), and The Patient’s Book of Natural Healing (Prima, 1999). Currently he is the Endowed Professor of Nutrition at Bastyr University of Natural Health Sciences, Kenmore, WA.

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