Source: The Cochrane Database of Systematic Reviews 2008, Issue 3
Research: A total of 37 trials, including 26 comparisons with placebo and 14 comparisons with synthetic standard antidepressants, met the inclusion criteria for an analysis of St. John’s Wort. Results of placebo-controlled trials showed marked heterogeneity. Trials comparing hypericum extracts and standard antidepressants were statistically homogeneous. Patients given hypericum extracts dropped out of trials due to adverse effects less frequently than those given older antidepressants; such comparisons were in the same direction, but not statistically significantly different, between hypericum extracts and SSRIs.
Results: Current evidence regarding hypericum extracts is inconsistent and confusing. In patients who meet criteria for major depression, several recent placebo-controlled trials suggest that the tested hypericum extracts have minimal beneficial effects, while other trials suggest that hypericum and standard antidepressants have similar beneficial effects. As the preparations available on the market might vary considerably in their pharmaceutical quality, the results of this review apply only to the products tested in the included studies. Researchers found that St. John’s Wort extracts were not only effective, but also that fewer people taking them dropped out of the trials due to adverse side effects.