Order does matter: the combined effects of classical conditioning and verbal suggestions on placebo hypoalgesia and nocebo hyperalgesia
Open Access
- 25 January 2021
- journal article
- research article
- Published by Ovid Technologies (Wolters Kluwer Health) in Pain
- Vol. 162 (8), 2237-2245
- https://doi.org/10.1097/j.pain.0000000000002211
Abstract
In most experimental studies in which verbal suggestion and classical conditioning are implemented together to induce placebo effects, the former precedes the latter. In naturally occurring situations, however, the information concerning pain does not always precede but often follows the pain experience. Moreover, this information is not always congruent with experience. This study investigates whether the chronology of verbal suggestion and conditioning, as well as their congruence, affect placebo hypoalgesia and nocebo hyperalgesia. The effects induced in 15 groups were compared. The participants in eight experimental groups were presented with verbal suggestions that were either congruent or incongruent with classical conditioning. The verbal suggestions were provided either before or after conditioning. In two other experimental groups, placebo conditioning or nocebo conditioning were implemented without any verbal suggestion; in two groups, verbal suggestion of hypoalgesia or hyperalgesia without conditioning was applied. The control groups without any suggestions or conditioning were also included. Placebo hypoalgesia induced by congruent procedures was significantly stronger when the suggestion of hypoalgesia preceded rather than followed conditioning. The order of the congruent procedures did not affect the magnitude of nocebo hyperalgesia. In the groups in which incongruent procedures were implemented, placebo hypoalgesia or nocebo hyperalgesia was in line with the direction of the last-used procedure, regardless of whether it was conditioning or verbal suggestion. The results show that not the type of the procedure (verbal suggestion or conditioning) but the direction of the last-used procedure shapes pain-related expectancies and determines placebo effects.Keywords
This publication has 53 references indexed in Scilit:
- Nonconscious activation of placebo and nocebo pain responsesProceedings of the National Academy of Sciences of the United States of America, 2012
- The Effects of Demand Characteristics on Research Participant Behaviours in Non-Laboratory Settings: A Systematic ReviewPLOS ONE, 2012
- The relation of emotions to placebo responsesPhilosophical Transactions Of The Royal Society B-Biological Sciences, 2011
- How placebo responses are formed: a learning perspectivePhilosophical Transactions Of The Royal Society B-Biological Sciences, 2011
- Studies Comparing Numerical Rating Scales, Verbal Rating Scales, and Visual Analogue Scales for Assessment of Pain Intensity in Adults: A Systematic Literature ReviewJournal of Pain and Symptom Management, 2011
- The Effect of Treatment Expectation on Drug Efficacy: Imaging the Analgesic Benefit of the Opioid RemifentanilScience Translational Medicine, 2011
- How the number of learning trials affects placebo and nocebo responsesPain, 2010
- How prior experience shapes placebo analgesiaPain, 2006
- The role of awareness in Pavlovian conditioning: Empirical evidence and theoretical implications.Journal of Experimental Psychology: Animal Behavior Processes, 2002
- Subject effects in laboratory research: An examination of subject roles, demand characteristics, and valid inference.Psychological Bulletin, 1972