Move over Prozac: Mother Nature has her own brand of antidepressant. It's an herb known as St. John's wort, and it works.

Extracts of the herb are effective in the treatment of mild to moderate depression, according to a recent Cochrane Review, part of a database that provides summaries and interpretations of high-quality medical research.

The review, performed by scientists at the Center for Complementary Medicine in Munich, Germany, analyzed findings from 29 clinical trials that included more than 5,000 participants from several countries. Based on the results of these trials, the German researchers concluded that extracts of St. John's wort are not only superior to placebo, they are just as effective as many commonly prescribed prescription drugs in the treatment of depression.

Even better, the plant extracts proved to have fewer adverse side effects than the prescription medications.

An earlier study published in the British Medical Journal showed that extracts of St. John's wort were at least as effective as Paroxetine, an antidepressant drug marketed under the brand name Paxil. At the end of the six-week trial, half of the patients taking St. John's wort experienced improvements in their symptoms, while only a third of those taking Paroxetine reported similar results.

Antidepressant medications are among the most commonly prescribed drugs in the United States. A report published by the Centers for Disease Control and Prevention revealed that adult use of antidepressants nearly tripled between 1988 and 2000. Antidepressant use among children more than doubled from 1995 to 2002.

St. John's wort, known in scientific circles by its Latin name, Hypericum perforatum, is a medicinal herb that has been used to alleviate symptoms of depression for centuries. According to an ancient legend, if the flowers and leaves of the herb are gathered on June 24, the birthday of St. John the Baptist, they have the power to ward off evil spirits.

The active ingredients in St. John's wort are believed to be hypericin and hyperforin, chemical compounds present in most commercially available preparations of the herb. Some experts speculate that other ingredients in the plant, including flavonoids and essential oils, also contribute to its antidepressant actions.

Although the exact mechanism of action is unknown, scientific evidence suggests that compounds in St. John's wort prevent the breakdown of specific neurotransmitters in the brain, including serotonin. In humans, serotonin helps promote a sense of well-being, improve sleep, increase tolerance to pain and reduce appetite.

Like St. John's wort, several prescription antidepressants reduce symptoms of depression by increasing levels of serotonin in the brain. Unfortunately, many of these drugs produce a variety of unpleasant side effects, including excessive daytime sleepiness, sexual dysfunction and even an increased risk of suicide.

While St. John's wort is best known for its ability to alleviate symptoms of depression, it is also valued for its ability to kill germs and reduce swelling. Topical preparations are used as antibacterial and anti-inflammatory agents to promote healing of minor burns and other superficial skin wounds.

The mild sedative effects of St. John's wort make it useful in the treatment of anxiety and insomnia. Research suggests it may help reduce symptoms of premenstrual syndrome, including uterine cramping, irritability, food cravings and breast tenderness.

In animal studies performed at the University of North Carolina at Chapel Hill, extracts of St. John's wort were found to reduce alcohol craving and consumption. Using rats selectively bred to prefer alcohol to water, the scientists found that rodents treated with the herb consumed 50 percent less alcohol than the untreated animals.

St. John's wort is widely available in the United States in the form of capsules, tablets, teas and tinctures. Findings from numerous clinical trials suggest the best dose for most adults is 900 milligrams daily, in two or three divided doses.

Some individuals report improvements in depressive symptoms within days of beginning treatment. Because blood levels continue to rise gradually over a period of several weeks, the full effects of the herb make take up to a month to manifest.

When taken alone and in therapeutic doses, St. John's wort is safe and well-tolerated by most individuals. Although the herb may potentially interact unfavorably with some prescription medications, the most commonly reported side effect is gastrointestinal upset.

If you're considering taking St. John's wort for depression, it's important to discuss your plans — and your symptoms — with your physician first. Depression is a serious illness that warrants professional medical treatment.

Rallie McAllister is a board-certified family physician, speaker, and the author of several books, including "Fitness and Healthy Lunchbox: The Working Mom's Guide to Keeping You and Your Kids Trim." Her website is www.rallieonhealth.com. To find out more about Rallie McAllister, M.D., and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.

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