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St. John’s wort: Let caution prevail when it comes to this depression ‘cure’

Modern-day Germany may take the credit for making St. John’s wort nature’s remedy du jour, but even ancient Greeks hailed the humble weed for its mood-altering powers. Extracts from the plant have long been included in teas as a calming agent. But lately, the herb has been heralded as an antidepressant in the same league as Prozac.

So should depressed people rip up their prescriptions and stock up on off-the-shelf St. John’s wort? Well, it’s not advisable based on the current evidence. First, note that the study published in the British Medical Journal that propelled the herb into the limelight analyzed the results of 23 small German studies, not one of which lasted longer than six weeks. Moreover, because the studies were conducted independently, standardized dosages were not used. Some of the studies used placebos; others did not. Only three compared St. John’s wort to other antidepressants, but they were older varieties—not the newer Prozac or Paxil.

Nonetheless, the overall findings of the study published in the British Medical Journal indicated that St. John’s wort may indeed help ease mild to moderate depression. That was compelling enough to grab the attention of the National Institutes of Health, which embarked on a study to answer some basic questions about St. John’s wort, such as: How does it work? What are safe, effective dosages? What are the long-term risks and benefits? Experts already knew St. John’s wort could disrupt the body’s ability to absorb iron and other minerals and possibly increase the skin’s sensitivity to the sun. What they also found was that there was a significant drug interaction between St. John’s wort and indinavir, a protease inhibitor used to treat HIV infection, and between St. John’s wort and cyclosporine, a drug used to prevent organ-transplant rejection.

Until we have more information, it’s wise to exercise caution regarding St. John’s wort. If you have symptoms of depression, such as prolonged sadness, changes in sleeping or eating patterns and loss of pleasure, talk to your healthcare provider. And if you are already being treated for depression, don’t take the herb in addition to or instead of the medications your healthcare provider has prescribed.