OBJECTIVE: The present study was designed to assess the role of endogenous opioids in the relationship of hypertension to repressive coping. METHODS: Ten hypertensive and 8 normotensive males were given either the opioid antagonist naltrexone or placebo in a randomized, double-blind fashion over the course of four laboratory sessions. Measures of repression and disclosure were completed and blood pressure was assessed during a laboratory stressor protocol. RESULTS: Opioid antagonism reduced repression and increased disclosure only in the hypertensive group. Also, opioid antagonism increased stress-related systolic blood pressure only in the hypertensive group. CONCLUSION: The results support the hypothesis that endogenous opioid dysregulation underlies both hypertension and repressive phenomena. Copyright © 2006 by the American Psychosomatic Society.