The transfer of conditioned and extinguished placebo hypoalgesia across contexts.

Although previous research has observed generalisation of placebo hypoalgesia between discrete treatment cues, generalisation across diffuse features of the treatment context is yet to be demonstrated. This study aimed to determine whether placebo hypoalgesia established in a specific context (A) could generalise to a new context (B) and whether extinction of placebo hypoalgesia in the new context (B) could be renewed when later tested back in the original context (A). Placebo hypoalgesia was induced via verbal instruction and a typical conditioning paradigm involving pairing a sham TENS device with reduced shock intensity. Participants were randomly allocated to two conditions differing by the context in which placebo hypoalgesia was extinguished. One group of participants was conditioned in Context A, extinguished in Context B, and then re-tested in Context A (Change Group), whereas the other group of participants were conditioned, extinguished, and re-tested in the same Context A (Consistent Group). There was clear evidence of placebo hypoalgesia across groups which extinguished over time, F(1,68) = 4.48, p <.038, ηp2 =.014. There were, however, no differences in the size or rate of extinction between groups Furthermore, no renewal of placebo hypoalgesia was observed in the renewal phase. These results demonstrate strong generalisation in both the expression and extinction of placebo hypoalgesia across features of the treatment context. These findings imply that positive experiences with pain treatments could transfer across different contextual cues within clinical settings. PERSPECTIVE: This article presents an experiment finding that the expression and extinction of placebo hypoalgesia generalises strongly across contextual cues. Clinicians managing pain in patients should note that individual experiences, both positive and neutral, may continue to influence subsequent experiences despite changes within treatment settings.