The placebo response can also be evident with procedures and medical devices. A particularly powerful example of the effect of placebo was published in the New England Journal of Medicine in 1959. For the 20 years prior to this article, angina had been treated by ligation of the internal mammary artery, under the assumption that blood flow to the myocardium could be increased. However, Cobb et al. showed that patients who were anesthetized and received sham incisions fared just as well as those with the real procedure. In fact, studies showed that both interventions could produce significant (70%) decrease in angina and increase in exercise tolerance (Cobb et al. 1959). This study conclusively demonstrated that procedures could have a powerful placebo effect.
On occasion, the placebo effect from an invasive procedure can be even more powerful than the placebo effect from medication. In 2006, Kaptchuk et al. examined the effects of sham acupuncture compared to a sham pill on patients with arm pain due to repetitive stress injury. They found that over the course of the trial, improvement in pain score and symptom severity scale increased in the group receiving sham acupuncture more than in the group receiving the sham pill (Kaptchuk et al. 2006).
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