title: Induced fear reduces the effectiveness of a placebo intervention on pain.
abstract: Fear was induced by the anticipation of electric shock in order to investigate whether fear reduced the effectiveness of a placebo intervention on reported pain and the acoustic startle reflex. Thirty-three subjects participated in a 3 Condition (Natural History [NH], Placebo [P], Placebo+Fear [PF])×3 Test (Pretest, Posttest 1, Posttest 2) within-subject design, tested on 3 separate days. Measures of fear were fear of pain (FOP), measured by the Fear of Pain Questionnaire (FPQ-III); fear-potentiated startle; and a self-report measure that assessed the effectiveness of the fear induction procedure. In the pain intensity data, there was a trend towards a placebo effect. This trend was abolished by induced fear, and was most pronounced in subjects who were highest in measures of fear. The placebo manipulation also caused a reduction in startle reflex amplitude. This effect was abolished by induced fear, and was strongest amongst high FOP subjects. In conclusion, induced fear abolished placebo analgesia, and this effect was strongest in subjects who had high scores on measures of fear.
authors.affiliation: Department of Psychology, Faculty of Health Sciences, University of Tromsø, Tromsø 9037, Norway.
authors.forename: Peter Solvoll
authors.initials: PS
authors.lastname: Lyby
authors.forename: June Thorvaldsen
authors.initials: JT
authors.lastname: Forsberg
authors.forename: Ole
authors.initials: O
authors.lastname: Åsli
authors.forename: Magne Arve
authors.initials: MA
authors.lastname: Flaten
mesh_terms: D000328:Adult; D000698:Analgesia / Q000379:methods*; D004558:Electric Stimulation; D005239:Fear / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000188:drug therapy / Q000523:psychology*; D059408:Pain Management; D015990:Placebo Effect; D010919:Placebos / Q000627:therapeutic use
chemical_list: D010919:Placebos