In the car on the way to the family Christmas gathering, Jeff read to us about a series of studies on placebos. For some conditions, placebos can give significant relief. There's still an effect even when subjects are told "You are taking an inert pill" and given a bottle marked "Placebo." Placebos given by providers who spend more time schmoozing with patients create more relief. (Note that I haven't found the actual studies concerned, so I don't know the effect sizes, etc.)
