St John's wort is as effective as antidepressants, according to researchers in Germany. The scientists from Charite Medical University in Berlin set out to establish the effectiveness of the herb by comparing it to the antidepressant drug, Paroxetine.

The research, which was published in the British Medical Journal, found that half of those who took St John's wort for six weeks found their symptoms in decline, while only a third of those taking Paroxetine went into remission. In previous studies St John's wort had been found to be more effective than a placebo in the treatment of mild to moderate depression but its efficacy compared to antidepressant drugs was unclear.

"The results thus indicate that in a group of patients in whom the appropriateness of hypericum (St John's wort) extract was previously disputed, the antidepressant efficacy of the herbal drug is at least comparable with the effect of one of the leading synthetic antidepressants," write the authors of the research.

Around 300 men and women aged 18-70 who had moderate to severe depression were recruited for the study. They were given either 900mg of the hypericum extract WS 5570 three times a day, or 20mg a day of Paroxetine.