Posttraumatic stress disorder may be associated with impaired fear inhibition: Relation to symptom severity

• Type of Material: Article
• Authors: Tanja Jovanovic, Emory University; Seth Davin Norrholm, Emory University; Jennifer E. Fennell, Atlanta Veterans Affairs Medical Center; Megan Keyes, Atlanta Veterans Affairs Medical Center; Ana M. Fiallos, Emory University; Karyn M. Myers, Center for Behavioral Neuroscience; Michael E Davis, Emory University; Erica Duncan, Emory University
• Language: English
• Date: 2009-05-15
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2008 Elsevier Ireland Ltd. All rights reserved.
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.psychres.2007.12.014
• Title of Journal or Parent Work: Psychiatry Research
• ISSN: 0165-1781
• Volume: 167
• Issue: 1-2
• Start Page: 151
• End Page: 160
• Grant/Funding Information: This research was supported by the Mental Health Service, Atlanta DVA Medical Center; the STC Program, the Center for Behavioral Neuroscience, of the National Science Foundation under Agreement No. IBN-9876754 (Venture grant, PI, E. Duncan); the American Psychiatric Association/Glaxo SmithKline (PI, E. Duncan); National Institute of Mental Health Grants 1R24MH067314-01A1 (PI, B. Rothbaum), R37 MH47840 (PI, M. Davis), Kirschstein National Research Service Award Individual Fellowship 1F32 MH070129-01A2 (PI, T. Jovanovic) and the Woodruff Foundation, Emory University School of Medicine.
• Keywords: PTSD; Classical Conditioning; Acoustic Startle Response; Electromyography; Fear-Potentiated Startle; Human
• Research Categories: Health Sciences, Rehabilitation and Therapy; Psychology, Behavioral; Biology, Neuroscience

Abstract

One of the central problems in posttraumatic stress disorder (PTSD) is the inability to suppress fear even under safe conditions. The neural underpinnings of fear is a clinically relevant issue that is poorly understood. This study assessed fear potentiation and fear inhibition using fear-potentiated startle in a conditional discrimination procedure (AX+/BX-). We hypothesized that patients with PTSD would show normal fear potentiation and impaired fear inhibition. 28 healthy volunteers and 27 PTSD patients (14 with low current symptoms, 13 with high current symptoms) were presented with one set of colored lights (AX trials) paired with aversive air blasts to the throat, and a different series of lights (BX trials) presented without air blasts. We then presented A and B together (AB trials) to see whether B would inhibit fear potentiation to A. All groups showed robust fear potentiation in that they had significantly greater startle magnitude on AX trials compared to noise alone trials. However, the high symptom PTSD group did not show fear inhibition: these subjects had significantly greater fear potentiation on the AB trials than both the controls and the low symptom PTSD patients.