St John’s Wort (hypericum perforatum) has a long history in medicine and has been used to treat everything from depression to battle wounds to tuberculosis. Though it is considered a weed by gardeners and farmers and can be poisonous to grazing animals, modern studies have shown it be effective in the treatment of depression. It is often also recommended as a treatment for anxiety; however clinical trials have shown that it has no positive impact when used to treat problems such as Social Anxiety Disorder.
What is St John’s Wort?
St John’s Wort is a perennial plant that reaches up to three feet in height. It possesses bright, yellow flowers and pale green leaves with oil glands. The plant is native to Europe but since the age of colonial expansion it has been introduced across the globe. It is considered a weed by farmers, as it can invade and strangle local ecosystems and render land useless for cultivation. When consumed by grazing animals it can lead to an increased sensitivity to light, depression of the central nervous system, abortion of gestating young and even death.
Medicinal Properties of St John’s Wort
Despite its poisonous nature, knowledge of the medicinal value of the plant dates back many centuries. Derivatives of St John’s Wort were used as anti-inflammatory, anti-bacterial and disinfecting agents by the Ancient Greeks; native Americans used tea brewed from the plant to treat respiratory disorders; in the middle ages it was used to treat battle wounds during the Crusades.
Today it is known to contain a number of active agents that can suppress or increase the concentration of a various human hormones. Ongoing studies exist to investigate its use in treating conditions ranging from premenstrual syndrome to Parkinson’s disease.
St John’s Wort for Depression
Clinical tests have shown that St John’s Wort may be as effective as over the counter antidepressant drugs such as Prozac at treating depression, while it also causes fewer side effects. Some critics have argued that there is a geographical skew to the research; scientists in Germany, where St John’s Wort is a particularly common treatment for depression, generally produce the most positive results. However even taking this into account, administration of St John’s Wort extracts appears significantly better than a placebo in treatment of depression.
It is believed that the main chemical agent responsible for combating depression is hyperforin. St John’s Wort is the only known plant in which this substance is found in great concentrations. Hyperforin acts as a reuptake inhibitor of serotonin, leading to greater concentrations of serotonin in the brain. High serotonin levels are linked to positive moods and so by increasing serotonin levels St John’s Wort can actively lift a patient out of a depressed state.
St John’s Wort for Anxiety
Conversely, scientists currently have no conclusive evidence to show that St John’s Wort is effective in combating anxiety. Anxiety and depression are often considered to be two sides of the same coin; yet depression is characterised by a physical slump while those suffering from anxiety are more likely to experience hypertension. People suffering from depression often experience periods of anxiety and vice versa, but it should be understood that they are distinct conditions requiring distinct treatments.
Because of the association this distinction can be blurred in people’s minds. St John’s Wort is often recommended for anxiety because of its success in treating depression. However, a 2005 study in the Journal of Clinical Psychopharmacology found that it was no better than a placebo in treating Social Anxiety Disorder, and there is little other available evidence to contradict this view.
St John’s Wort Side Effects
The potential side effects of St John’s Wort when taken on its own are generally mild. The most common reported side effects are dry mouth, dizziness, gut problems, tiredness and increased sensitivity to sunlight.
Care should be taken if combining the treatment with other drugs. St John’s Wort has been known to reduce the effect of some drugs while causing a potentially addictive effect in others. Birth control pills, SSRIs and cancer treatments are examples of drugs that should not be taken in conjunction with St John’s Wort, though there are many others.
St John’s Wort is a prolific plant seen as a noxious weed by most farmers. However, it has proven medicinal benefits when treating depression and may be helpful in treating a variety of other ailments. Clinical tests have shown it to be ineffective at treating anxiety and care should be taken when combing it with other medications. You should always consult a medical professional before starting a course of a St John’s Wort-derived product.
References:
Daily Mail, “’St John’s Wort as effective as Prozac for treating depression,’ say scientists’ (08 October 2008)
Kobak KA, Taylor LVH, Warner G, Futterer R, “St John’s wort versus placebo in social phobia: Results from a placebo-controlled pilot study” Journal of Clinical Psychopharmacology (2005)
Non-Timber Forest Products, “St John’s Wort”, (accessed 08 April 2010)
Patient.co.uk “St John’s Wort”, (accessed 08 April 2010)
