The new study reportedly contradicted at least 20 earlier studies that had shown the herbal treatment to be effective. Here's what you may have missed. All 200 participants had major depression and the previous studies showed the herbal remedy to be effective against mild to moderately severe depression.
Major depression is notoriously resistant to successful treatment of any kind.
In fact, all antidepressants are only marginally more effective than a placebo. This was confirmed in a 1999 government report based on an extensive review of all relevant clinical trials published between 1980 and 1998. The report noted that effectiveness in antidepressant drug trials is defined by something called the response rate. This refers to the percentage of the study participants whose depressive symptoms decrease by at least half. The next time a new clinical trial is announced, pay attention to its length.