Clinical Trials - What the Drug Companies Don't Report

The placebo effect is real. A 2002 University of Toronto study of brain scans revealed that Prozac and a placebo worked on similar areas of the brain (Prozac, though, worked on more areas of the brain).

With antidepressant drug trials, the placebo effect is high enough to cause a full half of these studies to end in failure, which has set off fierce debate over whether an antidepressant is little more than a placebo with side effects. The focal point of the controversy are two studies by Irving Kirsch PhD of the University of Connecticut:

A meta-analysis of nineteen nineteen double-blind antidepressant trials published in the American Psychological Association's online publication, Prevention and Treatment (Guy Sapirstein PhD of Westwood Lodge Hospital, Needham, MA, co-author) in 1998 caused an uproar in professional circles when it was revealed that the placebo effect accounted for a mind-boggling 75 percent of an antidepressant's result - any antidepressant, you name it.

Four years later, the July 2002 Prevention and Treatment published another study by Dr Kirsch that analyzed the FDA database of 47 placebo-controlled short-term clinical trials involving the six most widely prescribed antidepressants approved between 1987 and 1999. These included "file drawer" studies, ie trials that failed but were usually never published.

What Dr Kirsch and his colleagues found was that 80 percent of the medication response in the combined drug groups was duplicated in the placebo groups, and that the mean difference between the drug and placebo was a "clinically insignificant" two points on both the 17-item and 21-item Hamilton Depression Scale, regardless of the size of the drug dose. The placebo factor ranged from a high of 89 percent for the Prozac response, according to the study, and a low of 69 percent for the Paxil response. In four trials, the placebo equaled or achieved marginally better results than the drug. In the nine expert commentaries published with the study, none of the commentators disputed the study's main findings. Read full article....