Extracts of St John’s Wort have been used for a long time for anxiety and depression, but it is not clear how this herbal remedy performs as compared with other drugs or remedies or even as compared to placebo. Depression of various severities is such a widespread illness that it is a major public health problem, but many people do not want to take the synthetic antidepressants which have serious side effects. However, the chemical constituents are complex and it is not clear exactly what is the “active agent” of St John’s Wort.  

Reported in “Bandolier” is a systematic review of the effect of St John’s Wort (Hypericum) extracts as compared with a placebo or other kinds of antidepressants. The review of the literature found 23 studies. Of these 13 trials compared St John’s Wort with a placebo and the reduction of depression was rated as 22% in placebo and 55% with St John’s Wort. Clearly St John’s Wort has positive effects . But it can also be said that placebo does have some effect on its own ! However, studies comparing the effect of St John’s Wort against low dosages of other antidepressants showed no statistically significant differences in the trials. The authors of the review suggested that more research is necessary. Given the impact of placebo alone, it seems to be important to know the relative effects of levels and frequency of dosage, for example.