Intended for healthcare professionals

Rapid response to:

Editorial

Placebos in practice

BMJ 2004; 329 doi: https://doi.org/10.1136/bmj.329.7472.927 (Published 21 October 2004) Cite this as: BMJ 2004;329:927

Rapid Response:

Placebo Analgesia

A study published in the 1979 edition of Advances in Pain Research
and Therapy offered a tantalizing glimpse of a possible mechanism for
placebo analgesia.

A hundred or so patients who had wisdom teeth extraction were
assigned (random doule blind) to a fixed dose of an opiate (morphine, I
think) or the same volume of saline for post-operative analgesia. There
was no statistically significant difference in the proportion of patients
in the opiate versus the saline group who expressed satisfactory pain
relief. Placebo analgesia worked in a case of organic pain, post-operative
pain.

The researchers then broke the code after collecting analgesia data
and then randomised (again double blind) the saline responders to saline
or a dose of nalaxone. All the saline responders who got naloxone
complained of their pain again. This suggests that endogenous analgesic
systems involving enkephalins and/or endorphins might be involved.

So is placebo analgesia all in the mind? Or does the mind work via
known neuropharmacological pathways?

Those interested in looking the paper up will have to make do with
the following reference in non-standard manner:
Fields HL and Basbaum AI in Advances in Pain Research and Therapy, Vol.3
Ed Bonica JJ et al. Raven Press, New York 1979 pp427-440

Competing interests:
None declared

Competing interests: No competing interests

25 October 2004
Peter KK Au-Yeung
Specialist Anaesthetist
Hong Kong