What is St John’s wort?
It is a perennial herb with a yellow flower, that is commonly used to treat mild depression. It is sold as capsules, teas and extracts.

How Does It Work?
St John’s wort has many chemical compounds, some of which are believed to inhibit the reabsorption of serotonin, dopamine and noradrenaline. These are chemicals in the brain that are closely linked with depression.

Clinical trials have found that for mild or moderate depression St John’s wort is an effective treatment, and for some people it may be as effective as taking antidepressants. Interestingly, there are also many reports of people who have had no benefit from St John’s wort whatsoever. For severe or biological depression there is no evidence that St John’s wort is effective, and it carries significant risks in these cases.

What are the Pluses?

• It provides much needed relief for many people with mild or moderate depression
• It is an alternative for some people who find antidepressants to be ineffective
• The unpleasant side-effects experienced by some from anti-depressants may not be present
• Some aren’t willing to take antidepressants, but are happy to use herbal remedies
• The cost is a lot lower than antidepressants, and it is sold over the counter (except in Europe where it is widely prescribed).

What are the Minuses?

• In many countries where it is available over the counter, the active ingredients are not as precisely controlled as for drugs. Products can differ in content from brand to brand and batch to batch.
• It can interact with other medications, including antidepressants, HIV medications, some heart medications, the contraceptive pill and anticonvulsants for epilepsy. Treatment with St John’s wort needs to be medically supervised.
• Possible side effects include photosensitivity (increased sensitivity to sunlight), fatigue, dizziness and gastrointestinal symptoms
• It is not suitable for treating severe or melancholic / biological depression
• It shouldn’t be combined with many prescription drugs.

Further resources:
NCCAM - Herbs at a Glance
McMan’s Wort for Depression
Black Dog Institute Fact Sheet