As patients become more involved in their own health care and investigate the use of alternative medicines, it is ever more important to fully characterize the nature of these medicines. One such substance is St. John's Wort (Hypericum perforatum), regularly taken to treat depression. What remains to be established is whether or not St. John's Wort actually works. Results of studies have run the gamut from superior to placebo, to equivalent to other antidepressants to indistinguishable from placebo.
A recent study investigated the effects of hypericum on patients with well-defined major depression of moderate severity, and included a four-month continuation phase and sertraline as an active comparator. The trial was a randomized, double-blind, parallel-group eight week outpatient trial of hypericum, sertraline or placebo, followed by up to 18 weeks of double-blind continuation. The main outcome measures were changes in the Hamilton Depression scale (HAM-D) total score from baseline to eight weeks, and rates of full response, determined by the HAM-D and Clinical Global Impressions (CGI) scores.
Results were disappointing and somewhat unexpected. Not only could hypericum not be differentiated from placebo, neither could sertraline. Although the efficacy of sertraline was demonstrated on the secondary CGI-I measure, hypericum had no efficacy on any measure.
The study authors suggest a number of reasons for their results. The hypericum used in the trial was not standardized to hyperforin, which is possibly an important active ingredient. Also, it is possible that hypericum may be most effective in less severe major depression. The authors also conclude that perhaps the study lacked appropriate sensitivity. They suggest that this study outlines the importance of including an active comparator drug in a study. Without sertraline as an active comparator, the results would have been interpreted as evidence for a lack of efficacy of hypericum, without consideration of the possibility that a low assay sensitivity of the trial might have contributed to the finding.
Source
- Hypericum Depression Trial Study Group. Effect of Hypericum perforatum (St. John's wort) in Major Depressive Disorder. JAMA 2002; 287:1807-1814.
