Is placebo analgesia mediated by endogenous opioids? A systematic review

Pain. 1998 Jun;76(3):273-275. doi: 10.1016/S0304-3959(98)00057-8.


This systematic review assesses six experimental studies into the mechanism of placebo analgesia in human subjects suffering from clinical pain or experimentally induced ischaemic arm pain. Due to their sophisticated designs, these studies probably provide the best evidence that placebo analgesia exists. They also indicate that placebo analgesia is mediated by endogenous opiates. However, there seems to be room for additional studies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Analgesia*
  • Animals
  • Endorphins / physiology*
  • Humans
  • Placebo Effect*


  • Endorphins