[Note: St. John's wort may intereact with or reduce the effectiveness of a variety of commonly used prescription drugs and should be taken only under the guidance of a healthcare provider with a knowledge of botanical products.]
Background: In some countries extracts of the plant Hypericum perforatum L. (popularly called St. John's wort) are widely used for treating patients with depressive symptoms.
Objectives: To investigate whether extracts of hypericum are more effective than placebo and as effective as standard antidepressants in the treatment of major depression; and whether they have fewer adverse effects than standard antidepressant drugs.
Search Strategy: Trials were searched in computerized databases, by checking bibliographies of relevant articles, and by contacting manufacturers and researchers.
Selection Criteria: Trials were included if they: (1) were randomised and double-blind; (2) included patients with major depression; (3) compared extracts of St. John's wort with placebo or standard antidepressants; (4) included clinical outcomes assessing depressive symptoms.
Data Collection and Analysis: At least two independent reviewers extracted information from study reports. The main outcome measure for assessing effectiveness was the responder rate ratio (the relative risk of having a response to treatment). The main outcome measure for adverse effects was the number of patients dropping out due to adverse effects.
Main Results: A total of 29 trials (5,489 patients) including 18 comparisons with placebo and 17 comparisons with synthetic standard antidepressants met the inclusion criteria. Results of placebo-controlled trials showed marked heterogeneity. In nine larger trials the combined response rate ratio (RR) for hypericum extracts compared with placebo was 1.28 (95% confidence interval (CI), 1.10 to 1.49) and from nine smaller trials was 1.87 (95% CI, 1.22 to 2.87).
Results of trials comparing hypericum extracts and standard antidepressants were statistically homogeneous. Compared with tri- or tetracyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs), respectively, RRs were 1.02 (95% CI, 0.90 to 1.15; 5 trials) and 1.00 (95% CI, 0.90 to 1.11; 12 trials).
Both in placebo-controlled trials and in comparisons with standard antidepressants, trials from German-speaking countries reported findings more favorable to hypericum. [Where, the authors note, hypericum is commonly prescribed and the extracts used are controlled for content, so "results only apply to the preparations tested."]
Patients given hypericum extracts dropped out of trials due to adverse effects less frequently than those given older antidepressants (odds ratio (OR) 0.24; 95% CI, 0.13 to 0.46) or SSRIs (OR 0.53, 95% CI, 0.34-0.83).
Authors' Conclusions: The available evidence suggests that the hypericum extracts tested in the included trials:
a. Are superior to placebo in patients with major depression;
b. Are similarly effective as standard antidepressants;
c. And have fewer side effects than standard antidepressants.
The association of country of origin and precision with effects sizes complicates the interpretation.
Source: Cochrane Database of Systematic Reviews, Oct 2008 ;(4): PMID: 18843608, by Linde K, Berner MM, Kriston L. Centre for Complementary Medicine Research, Department of Internal Medicine II, Technische Universitaet Muenchen, Munich, Germany. [E-mail: Klaus.Linde@lrz.tu-muenchen.de]