title: Naltrexone alters the processing of social and emotional stimuli in healthy adults.
abstract: Endogenous opioids have complex social effects that may depend on specific receptor actions and vary depending on the "stage" of social behavior (e.g., seeking vs. responding to social stimuli). We tested the effects of a nonspecific opioid antagonist, naltrexone (NTX), on social processing in humans. NTX is used to treat alcohol and opiate dependence, and may affect both mu and kappa-opioid systems. We assessed attention ("seeking"), and subjective and psychophysiological responses ("responding") to positive and negative social stimuli. Based on literature suggesting mu-opioid blockade impairs positive social responses, we hypothesized that NTX would decrease responses to positive social stimuli. We also tested responses to negative stimuli, which might be either increased by NTX's mu-opioid effects or decreased by its kappa-opioid effects. Thirty-four healthy volunteers received placebo, 25 mg, or 50 mg NTX across three sessions under double-blind conditions. At each session, participants completed measures of attention, identification, and emotional responses for emotional faces and scenes. NTX increased attention to emotional expressions, slowed identification of sadness and fear, and decreased ratings of arousal for social and nonsocial emotional scenes. These findings are more consistent with anxiolytic kappa-antagonist than mu-blocking effects, suggesting effects on kappa receptors may contribute to the clinical effects of NTX.
authors.affiliation: a Department of Psychiatry and Behavioral Sciences , University of Texas Health Science Center at Houston , Houston , TX, USA.
authors.forename: Margaret C
authors.initials: MC
authors.lastname: Wardle
authors.affiliation: b Department of Psychiatry and Behavioral Neuroscience , University of Chicago , Chicago , IL , USA.
authors.forename: Anya K
authors.initials: AK
authors.lastname: Bershad
authors.affiliation: b Department of Psychiatry and Behavioral Neuroscience , University of Chicago , Chicago , IL , USA.
authors.forename: Harriet
authors.initials: H
authors.lastname: de Wit
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect / Q000187:drug effects; D001288:Attention / Q000187:drug effects*; D001794:Blood Pressure; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004644:Emotions / Q000187:drug effects*; D000066499:Facial Recognition / Q000187:drug effects*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D011581:Psychological Tests; D012938:Social Perception; D055815:Young Adult
chemical_list: D009292:Narcotic Antagonists; D009271:Naltrexone
keywords: Naltrexone; emotion perception; opiate system; psychophysiology; social processes