(Austin, TX). A new clinical study shows that a proprietary standardized extract of St. John's wort (SJW) was as effective as a common prescription antidepressant drug in reducing symptoms of depression. The study was published Friday, February 11 in the British Medical Journal.¹

According to the randomized, double-blind, reference-controlled trial, patients who took 900mg per day of a SJW extract known as WS® 5570 (W. Schwabe, Karlsruhe, Germany) had as much benefit as the pharmaceutical drug paroxetine (Paxil®, GlaxoSmithKline). Paroxetine is a prescription antidepressant drug in the class known as SSRI's (selective serotonin reuptake inhibitors). In some clinical outcomes, including the primary efficacy endpoint (a decrease of the depression scale score), WS 5570 was superior to the pharmaceutical antidepressant.

A reference-controlled trial is different than a placebo-controlled trial where some of the patients take a placebo (a dose with no active ingredient) as a control to test the effect of the herb or drug being studied. In a reference-controlled trial, the substance being tested is compared directly to a known active material, in this case, the FDA-approved prescription antidepressant drug, paroxetine.

The trial took place in various centers in Germany on patients from the ages of 18 to 70 during the years 2000 to 2003. The full treatment period was for 6 weeks. The patients had been diagnosed to have moderate to severe levels of major depression.

In the study, 251 patients were randomized to receive either 900 mg/day of WS 5570 or 20 mg/day of paroxetine. If a patient did not experience a measurable response after 2 weeks, the dose was doubled. Patients in the SJW group experienced significantly better improvement as measured by the Hamilton Depression Rating Scale (HAMD), an internationally accepted severity scale for depression.

The trial results showed that the SJW actually produced a better HAMD improvement than the pharmaceutical drug; patients in the SJW group experienced a three-point greater decrease in the average HAMD total score compared to the original scores (baseline) than did those taking paroxetine. The improvement in the SJW patients was considered clinically significant: there was a responder rate (50% improvement on HAMD) of 70% for the SJW patients versus 60% for those on paroxetine and a remission rate (HAMD equal or less than 10) of 50% for SJW versus 35% for paroxetine. Further, in the secondary efficacy measures (other standard depression scales including the clinical global impression), SJW was rated superior.

Regarding the safety aspects of the trial, the SJW produced significantly fewer adverse side effects than the drug. The paroxetine patients reported 269 adverse effects compared to only 172 for those on SJW. The most frequently reported adverse effect for both treatments was stomach upset, a fairly common side effect in many clinical trials of this type.

"This trial can help resolve some of the confusion surrounding the potential benefits of St. John’s wort," said Mark Blumenthal, founder and executive director of the nonprofit American Botanical Council. "Most of the clinical trials show that several types of St. John’s wort extracts produce clinically measurable and significant benefits."

The results of this trial are consistent with a previously published larger trial in France. In that double-blind, randomized, placebo-controlled trial conducted on 375 subjects, 900 mg per day of the same SJW extract (WS 5570) showed more benefit for depressed patients than did the placebo.²