title: Investigating the 'placebo personality' outside the pain paradigm.
abstract: OBJECTIVE
  To identify personality traits related to placebo responding outside the context of pain.
  
  
  METHODS
  Sixty three healthy volunteers completed the study. Personality traits were measured online one week prior to a laboratory session in which two psychosocial stress tests were administered. Prior to the second test, the placebo group received an intranasal spray of 'serotonin' (placebo) with the suggestion that it would enhance recovery. Subjective stress, heart rate and heart rate variability were measured. Self reported and physiological responses to the placebo suggestion were assessed against personality variables.
  
  
  RESULTS
  Placebo effects were demonstrated in both self reported and physiological stress metrics. Lower optimism and less empathic concern predicted greater perceived benefits from the placebo treatment; and lower drive, fun, and sensation seeking were related to a greater physiological response to the manipulation. Multivariate analyses revealed lower optimism and behavioural drive to be predictive of responding to the placebo manipulation.
  
  
  CONCLUSIONS
  Findings are in contrast with prior work in pain paradigms which found higher levels of the same traits to be related to greater placebo analgesic responses. A cluster of traits characterised by behavioural drive, extraversion, optimism and novelty or fun seeking appears to be germane to placebo responsiveness, but contextual stimuli may generate different patterns of responding. A new conceptualisation of placebo responsiveness may be useful. Rather than a 'placebo personality' it may be that responsiveness is better typified by a two faceted transactional model, in which different personality facets respond to different contextual contingencies.
authors.affiliation: Department of Psychological Medicine, University of Auckland, New Zealand. Electronic address: m.darragh@auckland.ac.nz.
authors.forename: Margot
authors.initials: M
authors.lastname: Darragh
authors.affiliation: Department of Psychological Medicine, University of Auckland, New Zealand.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Booth
authors.affiliation: Department of Psychological Medicine, University of Auckland, New Zealand.
authors.forename: Nathan S
authors.initials: NS
authors.lastname: Consedine
mesh_terms: D000328:Adult; D000339:Affect; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010465:Perception; D010551:Personality / Q000502:physiology; D015990:Placebo Effect
keywords: Heart rate; Personality; Placebo effect; Placebo responder; Stress recovery