WASHINGTON - They are widely prescribed, their effectiveness has been highly praised and many people consider them to be nothing less than life-savers. But is the effectiveness of drugs used to treat depression a product of their chemistry or the patients' psychological reaction to them? The authors of a meta-analysis of 19 drug studies involving 2,318 patients conclude that it may be the latter: three-quarters of the beneficial effect of anti-depressant medications, they contend, can be ascribed to the placebo effect - the patient's belief and expectation that the pill they are taking will make them better. Furthermore, the authors say, the remaining 25 percent of the positive effect of anti-depressants may be attributable to the fact that the drugs have side effects, which inert pills do not. The article, "Listening to Prozac but Hearing Placebo: A Meta-Analysis of Antidepressant Medication" appears in the premiere issue of APA's new online journal Prevention & Treatment, followed by commentaries from other psychologists and a psychiatrist, and a response from the lead author.
The authors, psychologists Irving Kirsch, Ph.D., of the University of Connecticut, and Guy Sapirstein, Ph.D., of Westwood Lodge Hospital in Needham, MA, pooled and analyzed the data from 19 randomized, placebo-controlled studies assessing the efficacy of various medications in treating depression, including some studies that involved drugs not considered anti-depressants. Looking across all 19 studies, the authors calculated the extent to which the beneficial effects of the various drugs could be attributed to the drugs themselves and the degree of positive effects that could be attributed to the placebo effect.
They concluded that 75 percent of the response to the drugs was a
placebo response and that, at most, 25 percent might be a true drug effect.
"This does not mean that only 25 percent of patients are likely to respond to
the pharmacological proper
Contact: Doug Fizel
American Psychological Association