Clinical significance of hyperforin for the efficacy of Hypericum extracts on depressive disorders of different severities

In a randomized, double-blind, placebo-controlled, multicenter study, the clinical efficacy and safety of two different extracts of St. John's wort were investigated in 147 male and female out-patients suffering from mild or moderate depression according to DSM-IV criteria. Fifty-six (38.1%) of them had an initial total score ≥ 22 points on the Hamilton Rating Scale for Depression (HAMD, 17-item version). Following a placebo run-in period of three to seven days, the patients were randomized to one of three treatment groups: During the 42-day treatment period, they received 3×1 tablet of either placebo, Hypericum extract WS 5573 (300mg, with a content of 0.5% hyperforin), or Hypericum extract WS 5572 (300 mg, with a content of 5% hyperforin). The manufacturing process for both Hypericum preparations was identical, they only differed with regard to their content of hyperforin. Efficacy regarding depressive symptoms was assessed on days 0, 7,14,28, and 42. The last observation of patients withdrawn from the trial prematurely was carried forward. At the end of the treatment period (day 42), the patients receiving WS 5572 (5% hyperforin) exhibited the largest HAMD reduction versus day 0 (10.3 ± 4.6 points; mean ± SD), followed by the WS 5573 group (0.5% hyperforin; HAMD reduction 8.5 ± 6.1 points) and the placebo group (7.9 ± 5.2 points). The monotonie trend was significant (Jonckheere-Terpstra test; p = 0.017). In patients with an initial HAMD total score ≥ 22, the HAMD reduction was even by 16.5% larger than in the total study group receiving WS 5572. More severely depressed patients treated with WS 5573, however, showed a 22.4% lower reduction of the HAMD total score than the entire WS 5573 treatment group. In patients with HAMD ≥ 22, WS 5572 showed a 53.8% larger HAMD reduction than placebo, whereas WS 5573 was not relevantly different from the placebo level. The mean HAMD reductions, treatment end versus baseline, for the more severely depressed patients were 12.0 (3.7) points, 6.6 (7.7) points and 7.8 (5.4) points [mean (SD)] for WS 5S72, WS 5573 and placebo, respectively. The results of a responder analysis support these findings. The data point to a dose-response relationship between the antidepressant efficacy of Hypericum extract and its hyperforin content. The extract with a higher content of hyperforin was particularly effective in patients who were more severely depressed.