Placebos can't cure diseases, but research suggests that they seem to bring some people relief from subjective symptoms, such as pain, nausea, anxiety and fatigue.
But there's a reason your doctor isn't giving you a sugar pill and telling you it's a new wonder drug. The thinking has been that you need to actually believe that you're taking a real drug in order to see any benefits. And a doctor intentionally deceiving a patient is an ethical no-no.
So placebos have pretty much been tossed in the "garbage pail" of clinical practice, says Ted Kaptchuk, director of the Program for Placebo Studies and the Therapeutic Encounter at Beth Israel Deaconess Medical Center. In an attempt to make them more useful, he's been studying whether people might see a benefit from a placebo even if they knew it was a placebo, with no active ingredients. An earlier study found that so-called "open-label" or "honest" placebos improved symptoms among people with irritable bowel syndrome.
And Kaptchuk and his colleagues found the same effect among people with garden-variety lower back pain, the most common kind of pain reported by American adults.
The study included 83 people in Portugal, all of whom had back pain that wasn't caused by cancer, fractures, infections or other serious conditions. All the participants were told that the placebo was an inactive substance containing no medication. They were told that the body can automatically respond to placebos, that a positive attitude can help but isn't necessary and that it was important to take the pills twice a day for the full three weeks.
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http://www.npr.org/sections/health-shots/2016/10/27/499475288/is-it-still-a-placebo-when-it-works-and-you-know-its-a-placebo?