This is something we know to be true already. The more invasive, the more powerful the placebo effect.
>Weirdly enough, surgery’s invasiveness may explain some of its potency. Studies have shown that invasive procedures produce a stronger placebo effect than non-invasive ones, said researcher Jonas Bloch Thorlund of the University of Southern Denmark. A pill can provoke a placebo effect, but an injection produces an even stronger one. Cutting into someone appears to be more powerful still.
Hmm. What happens when patients are given general anesthesia and just told they've had invasive surgery?
What if you supplement with a superficial incision and stitches, or a subdermal injection that causes some localized edema (and a dressing that obscures the fact there was no incision)?
>Weirdly enough, surgery’s invasiveness may explain some of its potency. Studies have shown that invasive procedures produce a stronger placebo effect than non-invasive ones, said researcher Jonas Bloch Thorlund of the University of Southern Denmark. A pill can provoke a placebo effect, but an injection produces an even stronger one. Cutting into someone appears to be more powerful still.
https://fivethirtyeight.com/features/surgery-is-one-hell-of-...