St John’s wort (Hypericum perforatum) is becoming increasingly popular as a herbal alternative to synthetic antidepressants for the treatment of mild to moderate depression.

Numerous placebo-controlled studies have shown that an extract of St John’s wort is clinically effective and has fewer and less severe side effects.

However, some have pointed out the design problems of these studies, and questioned whether the observed changes in depression scores reflect a true antidepressant effect.

To address these concerns, Dr Y Lecrubier, from Unité INSERM in Paris, and colleagues designed a six-week double-blind, randomized, placebo-controlled trial of St John’s wort extract WS 5570 in 375 outpatients suffering from a mild to moderate depressive episode according to DSM-IV criteria.

Patients were randomly assigned to one of two treatment groups – half received 300mg of WS 5570 three times per day and the other half received a placebo.

To assess drug efficacy, changes in the Hamilton Depression Rating Scale were recorded at follow-up visits held after one, two, four and six weeks.

Compared to placebo, WS 5570 produced a significantly greater reduction in total score on the Hamilton depression scale and resulted in significantly more patients with treatment response or remission.

The extract was more effective in patients with higher baseline Hamilton scores and led to global reduction of depression-related core symptoms, as assessed by the Bech melancholia subscale.

The two treatment groups had comparable adverse effects. However, the type, incidence and severity of these adverse events did not indicate any treatment-emergent risks associated with WS 5570, the authors note.

The researchers conclude that St John’s wort extract WS 5570 has an antidepressant effect in mildly and moderately depressed patients.

Reference: Lecrubier et al, American Journal of Psychiatry 2002;159:1361-1366

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