The placebo effect means that thinking that you’re getting some treatment of benefit can have actual benefits. This is well-established and no longer controversial.
But the effect goes even deeper. A study showed that expensive placebos work better.
If you buy an expensive drug and believe that it will be effective, it should be more effective.
If you tell people that they’re drinking expensive wine, they report that it tastes better than the cheap stuff, even though they both came from the same bottle.
This raises some interesting philosophical points: when you’re reporting a sensation like taste, there’s no way to distinguish between what’s “objectively” in the substance being tasted versus what being “added” by the mind.
Some parts of medicine are closer to that subjective wine taste than we like to think.