A systematic review and meta-analysis of Hypericum perforatum in depression: a comprehensive clinical review

The herbal remedy St John's wort is widely used as an antidepressant but it s efficacy has not been systematically investigated. Meta-analyses and syst ematic reviews of published trials strongly suggest St John's wort is more effective than placebo although comparative efficacy to standard antidepres sants is less clearly established. We updated and expanded previous meta-an alyses of St John's wort, scrutinised the validity of published reports and examined possible mechanisms of action. Twenty-two randomised controlled t rials were identified. Meta-analysis showed St John's wort to be significan tly more effective than placebo (relative risk (RR) 1.98 (95% CI 1.49-2.62) ) but not significantly different in efficacy from active antidepressants ( RR 1.0 (0.90-1.11)). A sub-analysis of six placebo-controlled trials and fo ur active comparator trials satisfying stricter methodological criteria als o suggested that St John's wort was more effective than placebo (RR 1.77 (1 .16-2.70)) and of similar effectiveness to standard antidepressants (RR 1.0 4 (0.94-1.15)). There was no evidence of publication bias. Adverse effects occurred more frequently with standard antidepressants than with St John's wort. The mechanism of action of St John's wort remains unknown. Future res earch should include large scale, appropriately powered comparisons of St J ohn's wort and standard antidepressants. Int Clin Psychopharmacol 16:239-25 2 (C) 2001 Lippincott Williams & Wilkins.