The placebo effect applies to other types of surgery as well. Back in 2002 there was a study published in the New England Journal of Medicine that concluded that arthroscopic knee surgery yielded results no better than placebo surgery. That article is cited in both of the linked articles at the bottom of this article, and also in this Wikipedia entry:<p><a href="https://en.wikipedia.org/wiki/Sham_surgery" rel="nofollow">https://en.wikipedia.org/wiki/Sham_surgery</a>
> The Cobb and Dimond mammary ligation studies show better than any drug study just how powerful the placebo effect can be. Angina is potentially debilitating. Yet the placebo effect brought pain down to manageable levels in people who had sham surgery, 80+ percent of the time. Is it any wonder acupuncture works for so many people? Or hypnosis? Or Prozac, Paxil, Celexa, Zoloft, Effexor, and all the rest?<p>Or, for that matter, psychological treatments, whether drugs, therapy or both.