A Cochrane review [Abstract] 1 included 29 trials (18 comparisons with placebo and 17 comparisons with synthetic standard antidepressants), with a total of 5 489 subjects. In trials restricted to patients with major depression, the combined response rate ratio (RR) for hypericum extracts compared with placebo from 9 larger trials was 1.28 (95% CI 1.10 to 1.49) and from 9 smaller trials 1.87 (95% CI 1.22 to 2.87). . Results of placebo-controlled trials showed marked heterogeneity. 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). Results of trials comparing hypericum extracts and standard antidepressants were statistically homogeneous. Both in placebo-controlled trials and in comparisons with standard antidepressants, trials from German-speaking countries reported findings more favourable to hypericum. Patients given hypericum extracts dropped out of trials due to adverse effects less frequently than those given older antidepressants (OR 0.24; 95% CI 0.13 to 0.46) or SSRIs (OR 0.53, 95% CI 0.34 to 0.83).
Comment: The quality of evidence is downgraded by inconsistency (variability in results across studies) and by potential reporting bias (selective publication of overoptimistic results in small trials).
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