Dalrymple on the placebo effect’s lesser-known cousin…

One of my first medical publications was on the nocebo effect, the unpleasant symptoms patients may suffer as a result of being made aware of potential side-effects of a treatment they are about to receive or a procedure they are to undergo. Thus patients who were having a lumbar puncture were either told or not told they might suffer a headache afterwards; and lo and behold, those who were told that they might get headaches duly got headaches while those who were not told didn’t.