Different Placebos, Different Mechanisms, Different Outcomes: Lessons for Clinical Trials.

ABSTRACT: Clinical trials use placebos with the assumption that they are inert, thus all placebos are considered to be equal. Here we show that this assumption is wrong and that different placebo procedures are associated to different therapeutic rituals which, in turn, trigger different mechanisms and produce different therapeutic outcomes. We studied high altitude, or hypobaric hypoxia, headache, in which two different placebos were administered. The first was placebo oxygen inhaled through a mask, whereas the second was placebo aspirin swallowed with a pill. Both placebos were given after a conditioning procedure, whereby either real oxygen or real aspirin was administered for three consecutive sessions to reduce headache pain. We found that after real oxygen conditioning, placebo oxygen induced

SUBMITTER: Benedetti F 

PROVIDER: S-EPMC4633056 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature