Efficacy of St. John's wort extract WS 5570 in major depression: a double-blind, placebo-controlled trial

In a double-blind, randomized, placebo-controlled trial with 375 patients the authors investigated the antidepressant efficacy and safety of 300 mg t.i.d. of hydroalcoholic Hypericum perforatum extract WS 5570.

The study participants were male and female adult outpatients with mild to moderate major depression (single or recurrent episode, DSM-IV criteria). After a single-blind placebo run-in phase, the patients were randomly assigned, 186 to WS 5570 and 189 to placebo, after which they received double-blind treatment for 6 weeks. Follow-up visits were held after 1, 2, 4, and 6 weeks. The primary outcome measure was the change from baseline in the total score on the 17-item Hamilton Depression Rating Scale. In addition, analyses of responders (patients with at least a 50% reduction in Hamilton total score) and patients with remissions (patients with a total score of 6 or less on the Hamilton scale at treatment end) were carried out, and subscale/subgroup analyses were conducted. The design included an adaptive interim analysis performed after random assignment of 169 patients with options for group size adjustment or early termination.

Compared to placebo, WS 5570 produced a significantly greater reduction in total score on the Hamilton depression scale and significantly more patients with treatment response or remission. It was more effective in patients with higher baseline Hamilton scores and led to global reduction of depression-related core symptoms, assessed with the melancholia subscale of the Hamilton scale. The placebo and WS 5570 groups had comparable adverse events.

H. perforatum extract WS 5570 was found to be safe and more effective than placebo for the treatment of mild to moderate depression.