title: Substance Use Attenuates Physiological Responses Associated With PTSD among Individuals with Co-Morbid PTSD and SUDs.
abstract: Posttraumatic stress disorder (PTSD) is often conceptualized from a fear conditioning perspective given individuals with PTSD demonstrate a reduced ability to inhibit fear even under safe conditions as compared to those without PTSD. The self-medication hypothesis suggests that individuals with PTSD often develop substance use disorders (SUDs) as an attempt to mitigate trauma-related distressing emotions. This investigation examined this hypothesis in a sample 214 participants, of which 81 did not meet criteria for either PTSD or SUDs (No diagnosis Control group); 33 met criteria for lifetime PTSD, but not SUDs (PTSD only group); 54 met criteria for lifetime SUDs, but not PTSD (SUDs only group); and 46 met lifetime criteria for both disorders (PTSD+SUDs group). PTSD was assessed using the modified PTSD Symptoms Scale (mPSS), SUDs were assessed using the Structured Clinical Interview for DSM-IV-TR (SCID). The startle magnitude was assessed using electromyography (EMG) of the eyeblink muscle in response to an acoustic startle probe. Fear-potentiated startle (FPS) was analyzed by comparing startle magnitude at baseline to startle during a fear conditioned stimulus. Results showed that PTSD significantly increased startle responses. However, there was a significant effect of SUDs on fear-potentiated startle to the danger signal, in that those who met criteria for SUDs had reduced fear compared to those who did not. The individuals who had co-morbid PTSD and SUDs did not differ from the Control group. Findings indicate that SUDs may attenuate exaggerated fear responses associated with PTSD. Consistent with the self-medication hypothesis, results suggest that substance use may co-occur with PTSD because it reduces heightened fear load and may allow normalized function in traumatized individuals.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, USA ; Mental Health Service, Atlanta VA Medical Center, USA.
authors.forename: Telsie A
authors.initials: TA
authors.lastname: Davis
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, USA.
authors.forename: Tanja
authors.initials: T
authors.lastname: Jovanovic
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, USA ; Mental Health Service, Atlanta VA Medical Center, USA.
authors.forename: Seth Davin
authors.initials: SD
authors.lastname: Norrholm
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, USA.
authors.forename: Ebony M
authors.initials: EM
authors.lastname: Glover
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, USA ; Department of Counseling and Psychological Services, Georgia State University, USA.
authors.forename: Mahogany
authors.initials: M
authors.lastname: Swanson
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Spann
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, USA ; Mental Health Service, Atlanta VA Medical Center, USA.
authors.forename: Bekh
authors.initials: B
authors.lastname: Bradley
keywords: Acoustic startle; Fear responding; Hyperarousal; PTSD; Substance abuse