title: Cognitive and emotional factors in placebo analgesia.
abstract: OBJECTIVE
  Information that a painkiller has been administrated induces an expectancy of reduced pain, and the expectancy has been shown to reduce pain. This is termed placebo analgesia. We hypothesized that an expectancy of reduced pain reduces stress.
  
  
  METHODS
  The present study (N=84) investigated this hypothesis. To further study the effects of stress and emotions on pain, we provided information about the pain stimulus to half the subjects. Pain was induced by the submaximum tourniquet technique.
  
  
  RESULTS
  Expectations and pain information both decreased pain to the same degree, but independently, and only in males. Lower pain was not related to subjective stress, cortisol, or circulating beta-endorphin. All experimenters were women, and the finding of placebo analgesia only in males fits well with findings that males report less pain to female experimenters.
  
  
  CONCLUSIONS
  Placebo analgesia is not related to stress and is influenced by the social context in which pain is recorded.
authors.affiliation: Department of Clinical Research, University Hospital of North, Tromsø, Norway. magnef@psyk.uit.no
authors.forename: Magne Arve
authors.initials: MA
authors.lastname: Flaten
authors.forename: Per Matti
authors.initials: PM
authors.lastname: Aslaksen
authors.forename: Arnstein
authors.initials: A
authors.lastname: Finset
authors.forename: Terje
authors.initials: T
authors.lastname: Simonsen
authors.forename: Oddmund
authors.initials: O
authors.lastname: Johansen
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage*; D000328:Adult; D000700:Analgesics / Q000008:administration & dosage*; D001143:Arousal / Q000187:drug effects; D003071:Cognition; D004644:Emotions; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007721:Knowledge of Results, Psychological; D008297:Male; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects*; D015990:Placebo Effect; D012718:Set, Psychology; D012737:Sex Factors; D013315:Stress, Psychological / Q000150:complications*; D001615:beta-Endorphin / Q000097:blood
chemical_list: D000700:Analgesics; D000082:Acetaminophen; D001615:beta-Endorphin; D006854:Hydrocortisone