Abstract

Exposure is a rapid and effective treatment for simple phobias. This study tested the assumption that endorphin release may be involved in exposure to a feared situation. Thirty spider-phobic Ss underwent exposure to 17 phobic-related, graded performance tasks. Half the Ss were randomly assigned to naltrexone, an opioid antagonist, and half to a placebo. Measures of heart rate, blood pressure, self-efficacy, anxiety, and cognitions were obtained during treatment. Six of the 15 Ss in the naltrexone group dropped out after the 10th step in the treatment compared with 1 of the 15 Ss in the placebo group, chi 2(1, N = 30) = 4.7, p = .03. The naltrexone group took significantly longer to complete the first 10 steps (the last step that included all Ss) compared with the placebo group, F(9, 252) = 2.17, p = .024. Maximum heart rate and anxiety were significantly greater at Step 10 in the naltrexone group, but no differences were found for self-efficacy or cognitions. The study provides further evidence that the endogenous opioid system may be involved in the process of exposure.

View details for Web of Science ID A1991FM54500008

View details for PubMedID 1677015