Endorphins and Placebo Fear Reduction

Abstract

This study examined whether endorphins play a role in placebo fear reduction in addition to their apparent mediation of placebo analgesia. 27 female undergraduate students were intravenously administered either saline or the endorphin antagonist, naloxone, under double-blind conditions prior to exposure to a nonspecific analogue treatment for snake fear. Analysis indicated that the two groups of subjects performed comparably and significantly better than no-treatment controls on posttest measures of self-efficacy, self-rated fear, and approach toward a live, harmless snake. These preliminary findings suggest that a mechanism other than endorphin release underlies fear reduction in psychological placebo treatments.