Depression: Does hypericum (St John's wort) help?

Some hypericum products may relieve mild to moderate depression, but have not been proven to make an impact on severe depression. Adverse effects are usually mild, but hypericum can interact with other drugs.

An estimated one out of six people suffers from depression at some point in their life. Depression is different from just being sad or feeling a bit moody or "blue". Typical signs of depression are feeling very low for at least two weeks and losing interest in things you usually enjoy. People who are depressed usually sleep badly, feel exhausted and have problems coping with everyday life. They lose their self-confidence and often withdraw from activities. Concentrating is difficult, and they have very negative thoughts about themselves.

Depression can be a single episode that lasts for weeks or months. Sometimes it will go away by itself, but often it will remain (chronic depression) or get worse. Depression can return (recurrent depression). Depending on the number and severity of symptoms, depression can be mild, moderate or severe. Severe depression is a very serious illness, and people with severe depression are at risk of suicide.

Depression can be treated with psychological therapies and/or drugs called antidepressants. People with milder forms of depression often use herbal remedies, including ones containing extracts of hypericum perforatum (the Latin name for "St John's wort"). As with most herbal medicines (phytopharmaceuticals), there is a wide variety of products made from hypericum on the market, with very different doses and ingredients. So there is no guarantee that the hypericum products you can buy have the same effect as the extracts that have been tested in trials. The amount of hypericum is very low in many products.

The regulations in Germany changed at the beginning of April 2009, so that some St John’s wort products are now only available on prescription. This only affects those for moderate depression though. The St John’s wort products that are used for other things, such as mild depression, are still available without a prescription.

You can read more about complementary (or "alternative") medicines in this fact sheet.

The review of research on the effect of hypericum

A group of researchers from the Cochrane Collaboration looked at trials that tested hypericum products to find out whether they can relieve depression in adults, and how they compare to other drugs for depression. In total they found 37 trials including nearly 5,000 people: 23 trials compared hypericum with a fake or dummy treatment (placebo), 11 trials compared it with other antidepressants and 3 trials compared it with both an antidepressant and a placebo. The trials lasted between 4 and 12 weeks and looked at a number of different hypericum products in various doses. About two thirds of the people in the trials had mild or moderate depression, and one third had severe depression. About 7 out of 10 of the people in the trials were women (70%).

The results for people with mild to moderate depression

The hypericum extracts used in the trials could relieve mild to moderate depression better than placebo treatment does. This may not be true for every hypericum product because the many products you can buy have different ingredients. There was not enough information from the trials to say how the different extracts compare with each other or what the best dose is.

Trials that compared hypericum with other antidepressants showed a similarly small effect for both treatments. At first this may sound like hypericum is as effective as other antidepressants in mild to moderate depression. But only three of the trials compared hypericum with both conventional antidepressants and placebo treatments. And they did not look at all of the antidepressants that are commonly used nowadays.

The results for people with major depression

The Cochrane researchers concluded that hypericum did not have an impact on severe depression in the trials. Severe depression is a serious illness, and self-treatment with hypericum alone does not appear likely to help.

Adverse effects and interactions with other drugs

Hypericum can cause adverse effects such as nausea, minor skin irritations, sensitivity to light (photosensitivity) and headaches. People can also be allergic to these products. The newer form of antidepressants called SSRIs (selective serotonin reuptake inhibitors) cause slightly more adverse effects than hypericum. Other types of antidepressants cause more adverse effects than both hypericum and SSRIs.

The biggest safety concern with hypericum, however, is interactions with other medicines. It is important that people who take more than one drug are aware of possible interactions between them. Like conventional medicines, taking herbal remedies such as hypericum together with other drugs can cause problems. For example, hypericum might affect the way some drugs work, especially blood-thinning drugs (like warfarin, or Marcumar) or drugs that influence the immune system (like cyclosporine, which suppresses the immune system). There is also some evidence that it can interfere with the way that the contraceptive pill works. If you are taking other medications, it is important that your doctor knows if you are using, or are planning to use, hypericum.


Author: German Institute for Quality and Efficiency in Health Care (IQWiG)

© IQWiG (Institute for Quality and Efficiency in Health Care)