Fear Extinction in Traumatized Civilians with Posttraumatic Stress Disorder: Relation to Symptom Severity

• Type of Material: Article
• Authors: Seth D. Norrholm, Emory University; Tanja Jovanovic, Emory University; Ilana W. Olin, Emory University; Lauren A. Sands, Emory University; India Karapanou, Emory University; Bekh Bradley-Davino, Emory University; Kerry Ressler, Emory University
• Language: English
• Date: 2011-03-15
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2011 Society of Biological Psychiatry
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.biopsych.2010.09.013
• Title of Journal or Parent Work: Biological Psychiatry
• ISSN: 0006-3223
• Volume: 69
• Issue: 6
• Start Page: 556
• End Page: 563
• Grant/Funding Information: Dr. Jovanovic has research support from NIMH (F32 MH070129).; Dr. Bradley has research support from the American Foundation for Suicide Prevention. Dr. Ressler has research support from NIMH (MH071537), National Centers for Research Resources (M01 RR00039), NARSAD, Burroughs Wellcome Foundation; Dr. Norrholm has research support from the National Alliance for Research on Schizophrenia and Depression (NARSAD), the Department of Defense (DOD)/Congressionally Directed Medical Research Program (CDMRP, Award # W81XWH-08-2-0170), the Emory University Research Committee, and PHS Grant (UL1 RR025008) from the Clinical and Translational Science Award program, National Institutes of Health, National Center for Research Resources.
• Keywords: Fear-potentiated startle; psychophysiology; fear extinction; anxiety disorders; trauma
• Research Categories: Psychology, General

Abstract

BACKGROUND The symptoms of PTSD can be explained, at least in part, as an inability to inhibit learned fear during conditions of safety. Our group has shown that fear inhibition is impaired in both combat and civilian PTSD populations. Based on our earlier findings, we employed an established fear extinction paradigm to further explore fear dysregulation in a civilian traumatized population. METHODS Fear-potentiated startle was examined in 127 trauma-exposed individuals with and without PTSD. We used a protocol in which conditioned fear was first acquired through the presentation of one colored shape (reinforced conditioned stimulus, CS+) that was paired with an aversive airblast to the larynx (unconditioned stimulus, US) and a different colored shape that was not paired to the airblast (nonreinforced condition stimulus, CS−). Fear was extinguished 10 minutes later through repeated presentations of the CSs without reinforcement. RESULTS Both groups demonstrated successful fear conditioning based on startle and US-expectancy ratings, however, participants with PTSD displayed greater fear-potentiated startle responses to the CS+ and CS− compared to the group without PTSD. During fear extinction, the PTSD group showed elevated fear-potentiated startle responses to the previously reinforced CS+ during the early and middle stages of extinction. During the acquisition and extinction phases, PTSD participants with higher levels of re-experiencing symptoms exhibited greater potentiated startle responses to the CS+ compared to PTSD participants with lower re-experiencing symptoms. CONCLUSIONS These results suggest that PTSD is associated with enhanced fear learning and a greater “fear load” to extinguish after conditioned fear is acquired.