Placebos in medicine: Is placebo analgesia always in the mind?

doi:10.1136/bmj.330.7481.45-b

BMJ 2005;330:45 (1 January), doi:10.1136/bmj.330.7481.45-b

Letter

Placebos in medicine

Is placebo analgesia always in the mind?

The first 150 words of the full text of this article appear below.

EDITOR—Spiegel discussed placebos in medicine.¹ A studypublished in the 1979 edition of Advances in Pain Research andTherapy offered a tantalising glimpse of a possible mechanismfor placebo analgesia.²

A hundred or so patients who had their wisdom teeth extractedwere assigned (random double blind) to a fixed dose of an opiateor the same volume of saline for postoperative analgesia. Thedifference in the proportion of patients in the opiate versusthe saline group who expressed satisfactory pain relief didnot reach significance. Placebo analgesia worked in a case oforganic pain, postoperative pain.

The researchers then broke the code after collecting analgesiadata and then randomised (again double blind) the saline respondersto saline or a dose of naloxone. All the saline responders whoreceived naloxone complained of their pain again. This indicatesthat endogenous analgesic systems of encephalins or endorphinsmight be important.

So . . . [Full text of this article]

Peter K K Au-Yeung, specialist anaesthetist

Department of Anaesthesia, Yan Chai Hospital, Tsuen Wan, New Territories, Hong Kong SAR, China lovpetay@netvigator.com