St. John’s Wort or Hypericum Perforatum is an herb that has been used for many centuries as a treatment for depression. It is very popular in Germany and in recent years people have done trials looking at whether it actually helps people who are depressed.

People who are depressed in the clinical sense are generally low in mood most days over some weeks or months and may lose interest in activities they normally enjoy. They often suffer from poor sleep and concentration and low energy or fatigue. Sometimes their appetite is disturbed and they may be anxious or agitated. In more severe cases the person may feel that life is not worth living or feel frankly suicidal. Depression typically lasts from 6 months to 2 years if left untreated and, if it is moderate or severe, professional help – initially from a general practitioner – is usually necessary. People whose depression is mild, even though it can be very distressing, often choose to manage it on their own. One of the interesting facts about any treatment for depression is that a placebo (or inactive pill) seems to work for about 20% of people. However in some trials more than 60% of people responded to St. John’s Wort compared with just under 60% for conventional antidepressants.

But is it safer to Take St. John’s Wort? The answer, as you might expect is ‘There are pros and cons’. Many prescribed medications are derived from herbs or plants such as Digoxin (from foxgloves) and Aspirin (from Willow). When made into tablets the exact dose is known whereas with so-called ‘natural preparations’ this is not always so clear. With prescribed medications it is the active extract that is made into tablets – in the case of St. John’s Wort it is thought that the active component is a substance called Hypericin but as the tablets are sold as a nutritional aid rather than a medicine the degree of purity is not controlled as tightly and the tablet may contain other components.

There have not been reports of serious side effects or toxicity in people who have taken overdoses. In studies the main side effects have been stomach upsets, allergic reactions and fatigue but only about 20% of people complain of these. This has to be compared with the side effects from modern antidepressants, which are not necessarily that bad. There is also not really any evidence about long term effects.  Recently there has been evidence of interactions with other drugs notably a drug used in the treatment of AIDS and one used to prevent rejection of organ transplants. There is also evidence of dangerous interaction with Digoxin and Warfarin (used for some heart and circulatory conditions).

In summary then, the current evidence suggests that St. John’s Wort may be as good as prescribed medicines for mild depression but less is known about it, particularly in the longer term and more research needs to be done. As it is available over the counter many people will use it so the rules to remember are – discuss its use with a pharmacist and if necessary a doctor, particularly if you are taking any other medication – as knowledge about interactions is changing all the time. If you do decide to take it and it is not working after a couple of weeks do consult your doctor, as many possible treatments are available for depression.