Brian Resnick in Vox:
The story of the placebo effect used to be simple: When people don’t know they are taking sugar pills or think they might be a real treatment, the pills can work. It’s a foundational idea in medicine and in clinical drug trials dating back to the 1950s.
Then Ted Kaptchuk came along.
Kaptchuk is a professor at Harvard Medical School, and over the past decade, he and colleagues have shown, in study after study, that giving people placebos openly — that is, telling them they are taking a placebo — helps them feel better. Specifically, they found a placebo can relieve not just pain but also anxiety and fatigue.
In February, Kaptchuk and his colleagues published the results of a clinical trial comparing these open-label placebos to double-blind placebos (the gold standard in medical research) in treating irritable bowel syndrome. Both were equally effective.