Posttraumatic Stress Disorder and Impaired Autonomic Modulation in Male Twins

• Type of Material: Article
• Authors: Amit J. Shah, Emory University; Rachel Lampert, Yale University; Jack Goldberg, University of Washington; Emir Veledar, Emory University; J. Douglas Bremner, Emory University; Viola Vaccarino, Emory University
• Language: English
• Date: 2013-06-01
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2013 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.biopsych.2013.01.019
• Title of Journal or Parent Work: Biological Psychiatry
• ISSN: 0006-3223
• Volume: 73
• Issue: 11
• Start Page: 1103
• End Page: 1110
• Grant/Funding Information: The United States Department of Veterans Affairs has provided financial support for the development and maintenance of the Vietnam Era Twin (VET) Registry.; This work was supported by the National Institutes of Health (K24HL077506, R01 HL68630, R01 AG026255, NIH K24 MH076955, R21HL093665-01A1S1) and by the American Heart Association (0245115N).; Also supported by the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Number UL1TR000454, and by the Emory University General Clinical Research Center MO1-RR00039.
• Keywords: military combat trauma; posttraumatic stress disorder; Autonomic nervous system; mental stress; heart rate variability; heart disease
• Research Categories: Health Sciences, Human Development; Health Sciences, Public Health

Abstract

Background Posttraumatic stress disorder (PTSD) has been linked to increased morbidity. An inflexibility of the autonomic nervous system may be the underlying mechanism. We aimed to assess whether PTSD and combat trauma exposure are associated with lower heart rate variability (HRV), a measure of autonomic function and a predictor of death. Methods We measured HRV by power spectral analysis on 24-hour ambulatory ECG in 459 middle-aged veteran male twins. Combat trauma was assessed with the combat exposure scale, and current and remitted PTSD with the Structured Clinical Interview for Psychiatry Disorders. Mixed-effects regression models were used to test associations of PTSD and HRV between and within twin pairs. Results Of all twins, 211 had combat exposure, 31 had current PTSD, and 43 had remitted PTSD. Current PTSD was inversely associated with very-low frequency (VLF) and low frequency (LF) HRV both in individual twins and within 20 pairs discordant for current PTSD. Twins with current PTSD had a 49% lower LF HRV than their brothers without PTSD (p<0.001). Remitted PTSD was not associated with HRV. Results were robust to adjustment for depression and other risk factors. Combat exposure was inversely associated with most HRV frequencies, but this association mostly diminished after adjustment for current PTSD. Conclusion In middle-aged veteran men, combat exposure and current PTSD are associated with measures of autonomic inflexibility previously shown to have prognostic significance. The negative health impact of combat exposure on autonomic function is mediated largely through PTSD and may reverse with remission of PTSD.