St. John's wort has been a popular drug in Europe for years. In Germany, where its use is covered by health insurance as a prescription drug, millions of people take preparations containing St. John's wort, and many of them use St. John's wort to treat depression.
How St. John's Wort Works for Depression
Among St. John's wort's chemical constituents are tannins, flavonoids, xanthones, terpenes, phloroglucinol derivatives, and carotenoids. Hypericin and hyperforin, two principal components, are reportedly important for alleviating depression, although other constituents may play a role as well. But how St. John's wort works remains unclear.
Early research in test tubes indicated that St. John's wort functions much like an MAO inhibitor. As a result, doctors advised patients who consumed the herb to shy away from tyramine-rich foods and medications. However, because no other evidence supports the MAO theory, and because no MAO inhibitor-like side effects have been seen with St. John's wort, it is not necessary to avoid foods or medications that contain tyramine when taking this herb.
Newer studies indicate that St. John's wort functions more like an atypical antidepressant, blocking re-uptake of serotonin and serotonin receptors. And some evidence suggests St. John's wort may work by regulating compounds secreted by white blood cells that communicate with the brain about mood -- think about how tired you feel when you have an infection and you can see the connection.
In whatever way St. John's wort carries out its biological functions, evidence is sound that the herb is effective in relieving mild to moderate symptoms of depression.
Evidence of St. John's Wort's Effectiveness
There have been more than 35 randomized, double-blind studies comparing St. John's wort, or Hypericum, with a placebo or antidepressant drugs. In most of those studies, researchers noted a statistically significant improvement among patients who took Hypericum.
So many studies have been done that it is necessary to consider them in groups to get a sense of whether St. John's wort is effective. Mathematically grouping and comparing studies in this way, as if one gigantic study had been done, is known as a meta-analysis.
Several meta-analyses on St. John's wort have been published. The most recent ones conclude that although there are some studies that do not agree, most studies show St. John's wort is effective for people with mild-to-moderate depression (compared to placebo, or dummy pill), and St. John's wort is far less likely to cause adverse effects than antidepressant drugs.
One of the most impressive studies to date involved 332 men and women with mild-to-moderate depression and was completed in Germany in 2006. Taking either 600 milligrams or 1,200 milligrams of a standardized extract of St. John's wort led to significantly better improvement in depression symptoms than taking placebo, and the two doses were similar to each other in efficacy after six weeks.
How Does St. John's Wort Compare?
There have been at least 14 randomized double-blind studies -- and scores of less-structured experiments -- comparing Hypericum with tricyclic antidepressants and SSRI drugs in patients suffering mild-to-moderate depression. In general, Hypericum has produced similar antidepressant effects that appear to grow stronger with length of treatment and have few adverse side effects.
Those findings prompted the British Medical Journal to write: "St John's wort is a promising treatment for depression. Hypericum extracts were significantly superior to placebos, and similarly effective as standard antidepressants. This herb may offer an advantage in terms of relative safety and tolerability, which might improve patient compliance."
At the Psychiatric Clinic in Darmstadt, Germany, 135 patients aged 18 to 75 were given either Hypericum extract or imipramine (Tofranil) three times a day for six weeks. The patients then were tested for depression with the Hamilton Depression Scale (HAM-D, a measurement of the severity of depression) and the Clinical Global Impressions Scale (CGI).
The mean HAM-D score fell from 20.2 to 8.8 in the Hypericum-treated group and from 19.4 to 10.7 in the imipramine-treated group. The CGI score, which measures therapeutic effectiveness, rose from 1.3 to 3.1 in the Hypericum group and from 1.2 to 2.7 in the group of subjects taking imipramine.
Adverse side effects were reported by eight patients on Hypericum and 11 patients on imipramine. But the reactions noted by Hypericum takers were less severe than those reported by imipramine patients.
Another randomized double-blind study compared Hypericum with amitriptyline (Elavil), given three times a day for six weeks to 80 patients with mild to moderate depression. The HAM-D score fell from 15.82 to 6.34 in the Hypericum group and from 15.26 to 6.86 in the amitriptyline group. There were twice as many complaints about adverse effects in the amitriptyline group -- 58 percent compared to 24 percent among Hypericum takers.
Yet another study that was performed during 2002 and 2003 compared the effectiveness of St. John's wort with the SSRI drug citalopram (Celexa) and placebo. The study followed 388 patients at several locations for six weeks. St. John's wort and citalopram both reduced the HAM-D scores by 55 percent by the end of the trial, showing nearly equal efficacy. This was superior to the 40-percent improvement reported by the placebo group. More than 50 percent of the citalopram group reported adverse effects, compared to 30 percent in the placebo group and just 17 percent in the St. John's wort group.
For important information on St. John's wort's potential side effects, continue to the next page.
For more information on treating and understanding depression, try the following links:
- To see all of our home remedies and the conditions they treat, go to our main Home Remedies page.
- Depression can quickly spiral into a serious and dangerous problem. While severe cases of depression need a doctor's attention, mild depression can be treated with herbs available at your local health-food store. Learn more in Herbal Remedies for Depression.
- You can learn more about the causes and treatments of depression in How Depression Works.
- To learn more about stress and how it can contribute to depression, read How Stress Works.
- One of the major factors that can cause depression is anxiety. Learn how to alleviate this condition in Home Remedies for Anxiety.
This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.