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NBC News
Even in severely depressed patients, the antidepressant drug, Zoloft, was no better than placebo.
Although promoted as an alternative therapy for depression, the herbal supplement St. John’s wort appears ineffective for people with moderate clinical depression, findings from a US study suggest. In the study of 340 patients diagnosed with moderate depression, St. John’s wort proved no more effective than inactive treatment with a placebo in alleviating symptoms. Active treatment with the antidepressant drug sertraline (Zoloft) worked somewhat better than placebo, according to findings published in the April 10th issue of The Journal of the American Medical Association (news - web sites).
A body of evidence suggests that St. John’s wort (Hypericum perforatum), used for more than 2,000 years to quell mood problems, does help symptoms of depression. In Germany, where many of the positive studies have been conducted, St. John’s wort is available as a prescription antidepressant.
But the quality of much of this research has been criticized—including the lack of studies using a placebo and a selective serotonin reuptake inhibitor (SSRI) like sertraline, according to the authors of the new study. SSRIs are a newer class of drugs commonly used to treat depression.
To address these concerns about earlier studies, researchers led by Dr. Jonathan R. T. Davidson of Duke University in Durham, North Carolina, randomly assigned patients to take St. John’s wort, sertraline or placebo for up to 26 weeks.
At the study’s end, the researchers found that neither the herb nor the drug was better than placebo in improving patients’ scores on a standard scale of depressive symptoms. Overall, nearly one third of placebo patients showed a full response to treatment, compared with roughly 24% in both the St. John’s wort and sertraline groups.
Patients on sertraline did, however, do better than placebo patients on a secondary test used to gauge a person’s daily functioning and levels of distress. The sertraline group also had a higher percentage of so-called “partial responders” to treatment than either the placebo or St. John’s wort groups.
Still, the findings do not indicate whether the herb can help people with mild depressive symptoms—a question additional research will have to address, Davidson told Reuters Health. St. John’s wort is marketed for the treatment of mild to moderate depression, but Davidson noted that it’s likely people with a range of depressive disorders try the herb.
“If someone is suffering from depression for weeks, they’re much better off going to a healthcare professional...than trying to self-treat,” he said.
And because St. John’s wort can interact with a range of drugs, including some used to treat cancer and HIV (news - web sites), people who do use the herb “should always tell their doctor they’re using it,” Davidson added.
As for the findings on sertraline, the researcher said that dosing “had a lot to do with” the lack of full response among patients on the drug. The study design permitted sertraline to be given only up to half of its highest recommended dose, and fewer patients on the drug had their doses “maximized,” compared with those on St. John’s wort or placebo.
Dosing “almost certainly contributed” to sertraline’s less-than-stellar performance in the study, according to an accompanying editorial by Drs. David J. Kupfer and Ellen Frank of the University of Pittsburgh Medical School in Pennsylvania.
They also stress that this study—along with a second one in the same journal issue documenting the rise of the “placebo effect” in recent research on depression drugs—highlight the importance of using a placebo and an active comparison drug in studies of unproven antidepressant agents.
The New York-based drug company Pfizer Inc. provided the sertraline for the study, and Lichtwer Pharma of Berlin, Germany, supplied the St. John’s wort product. Davidson holds stock in Pfizer, and has received speaker fees from both Pfizer and Lichtwer. Co-authors on the study have received funding from a number of pharmaceutical companies.
The study itself was funded by the US National Institutes of Health.
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