Overestimation of the Placebo Effect :: Biology Essays Research Papers

Overestimation of the Placebo Effect The purpose of this paper is to investigate whether the Placebo Effect is overestimated through misinterpretation of the data. Specifically, the objective is to explore whether the passage of time during clinical trials accounts for many results widely attributed to the placebo effect. That is, the passage of time in itself-through a combination of spontaneous changes in symptoms, regression effects, and homeostatic changes-produces most of the favorable results credited to the placebo. Despite its widespread acceptance for approximately fifty years, the Placebo Effect has recently become controversial, with several researchers claiming that the presumed benefits of placebos are overestimated. Dr. Asbjorn Hrobjartsson and Dr. Peter C. Gotzsche of the University of Denmark and the Nordic Cochran Center reviewed journal articles looking for the original research stating that 35% of patients improve if given a placebo. Interestingly, none of the papers they examined included original research on the placebo effect, but all cited the same reference. The original source was a 1955 article, "The Powerful Placebo," published in the Journal of the American Medical Association and written by Henry Beecher, chief of anesthesiology at Massachusetts General Hospital in Boston. Dr. Beecher had analyzed about a dozen studies and had come up with the 35% figure (1). Challenging the validity of this finding, Drs. Hrobjartsson and Gotzsche hypothesized that two important factors were ignored. First, that the natural course of many diseases is to wax and wane. Second, that a patient who feels terrible one day will almost certainly feel better the next day. Hrobjartsson and Gotzsche analyzed 114 studies conducted between 1946 and 1998 that used not the usual two, but three groups of patients. One group received appropriate medical treatment, one group received placebo treatment, and the third group received nothing. (The studies involved 7,500 patients with 40 different medical conditions, including high blood pressure, high cholesterol levels, asthma, behavior disorders, such addictions as alcohol abuse and smoking, and such neurological diseases as Alzheimer's Disease, Parkinson's Disease, epilepsy, as well as bacterial infections and the common cold (5). As Hrobjartsson and Gotzsche predicted, the patients in this third group improved as often as the patients in the placebo group (1). Carol Hart (2) cites Shapiro and Shapiro, who offer possible confounds that lead to overestimation of the placebo effect. Observations of the third control group-the group with neither treatment, nor placebo-may have improved because of three mechanisms.