Placebo Analgesia and the Role of Expectancy on Pain Perception
Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Expectancy in placebo analgesia is proposed to be one of the major mechanisms influencing placebo analgesic responses. Still, little is known of how these effects mediate pain perception. The notion of strong belief in placebo efficacy, i.e. placebo expectancy, was investigated by reviewing placebo analgesia literature, and other relevant studies. Placebo suggestions seem to involve reduced averseness of the impending stimulus, and not cognitively demanding tasks such as executive attention. Converging evidence has shown that positive and negative mood changes can affect both pain intensity and pain unpleasantness, which are both elements of subjective pain. Positive mood mostly seem to affect pain unpleasantness, whereas negative mood changes affect both pain intensity and pain unpleasantness, suggesting that there are two different ways that placebo expectancies can influence pain. One problem with functional imaging research in the realm of placebo analgesia is that activity is not compared with expectancy ratings. Therefore, the neural correlates of placebo expectancies, i.e. placebo belief, are largely unknown. Some findings suggest that dorsolateral prefrontal cortex (DLPFC) is involved in placebo analgesia. It is suggested that placebo analgesia is opioid dependent, seeing that expectancy induced analgesia is naloxone reversible. However, it probably acts through different mechanisms than administered opioids, seeing as placebo analgesia can be site-specific.
Place, publisher, year, edition, pages
2015. , 57 p.
placebo, analgesia, pain perception
IdentifiersURN: urn:nbn:se:his:diva-11674OAI: oai:DiVA.org:his-11674DiVA: diva2:868947
Subject / course