St John’s wort (Hypericum perforatum) is a perennial herb of the Hypericaceae family that has been used medicinally for centuries to treat mental health. In particular St John’s wort appears effective at treating mild depression and anxiety. In Germany St John’s wort is used as a prescription medication for depression and anxiety related disorders and in 1993 accounted for 2.7 million prescriptions. The active ingredient within St John’s Wort that gives it these beneficial effects has not been definitively identified, because the herb is a complex mix of many phytochemicals. These include flavonoids such as quercetin and the hyperforin xanthones which may both account for some of the biological effects of the herb. However most research has centred on the biologically activity of a group of naphthodianthrons including hypericin and pseudohypericin. Many preparations are now standardised for hypericin at 0.3 %, although other ingredients may play synergistic roles within the herb.
A number of studies have shown the efficacy of St John’s Wort at treating mild depression. In 1996, a meta analysis of previous studies was published in the British Medical Journal in order to investigate the clinical benefits of St John’s Wort1. A medline search was used to identify studies and 23 were selected for the analysis that included 1757 outpatients with mild or moderately severe depression. Of the studies fifteen compared St John’s Wort to a placebo tablet, whereas eight of the studies compared St John’s Wort to other medications for depression. The results of the meta analysis showed that hypericum extracts were significantly superior to placebo tablets in the treatment of depression. Further, the extracts of hypericum were as effective as standard antidepressants given as single preparations and in combinations. Interestingly, side effects were reported in 19.8 % of people taking St John’s Wort, whereas side effect were reported in 52.8 % of people taking standard antidepressants.
These results show that St John’s Wort is an effective treatment for depression and this is in agreement with the historical use of St John’s Wort to treat mental illness. Although the ingredient within St John’s Wort that is responsible for these effects has not been identified, nature shows us that herbs are effective because of synergistic effect of multiple nutrients present. St John’s Wort is generally well tolerated and side effects are mild, particularly when the whole herb is administered. One of the side effects is an increased photosensitivity, although this can actually be beneficial to those who desire such effects as it can allow the development of a broad tan without excessive sunlight exposure. St John’s Wort is available from health food shops and is also available as a decoction in the form of tea bags. Generally the herb has an exceptional safety record and data for such safety is available within the medical records from countries such as Germany were the herb is treated as a medicine and controlled in the same way.
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