ORIGINAL ARTICLE Posttraumatic Stress Disorder Mediates the Relationship Between Mild Traumatic Brain Injury and Health and Psychosocial Functioning in Veterans of Operations Enduring Freedom and Iraqi Freedom Robert H. Pietrzak, PhD, MPH,*† Douglas C. Johnson, PhD,‡ Marc B. Goldstein, PhD,§ James C. Malley, PhD, and Steven M. Southwick, MD*† Abstract: This study evaluated whether posttraumatic stress disorder (PTSD) mediated the relationship between mild traumatic brain injury (MTBI) and general health ratings, psychosocial functioning, and perceived barriers to receiving mental healthcare 2 years following return from deploy- ment in veterans of Operations Enduring Freedom and Iraqi Freedom (OEF/OIF). A total of 277 OEF/OIF veterans completed the Connecticut OEF/OIF Veterans Needs Assessment Survey; 18.8% of the sample screened positive for MTBI. Compared with respondents who screened negative for MTBI, respondents who screened positive for MTBI were younger, more likely to have PTSD, more likely to report fair/poor overall health and unmet medical and psychological needs, and scored higher on measures of psychoso- cial difficulties and perceived barriers to mental healthcare. Injuries involving loss of consciousness were associated with greater work-related difficulties and unmet psychological needs. PTSD mediated the relationship between MTBI and all of these outcomes. These results underscore the importance of assessing PTSD in OEF/OIF veterans who screen positive for MTBI. Key Words: Veterans, combat, soldiers, posttraumatic stress disorder, mild traumatic brain injury, psychosocial, functioning, barriers to care. (J Nerv Ment Dis 2009;197: 748 –753) A recent population-based study found that posttraumatic stress disorder (PTSD) and depression mediated the association be- tween mild traumatic brain injury (MTBI) and physical symptoms in a large sample of soldiers returning from Operations Enduring Freedom and Iraqi Freedom (OEF/OIF; Hoge et al., 2008). Specif- ically, soldiers who screened positive for MTBI were more likely to report poorer health and a high number of somatic (e.g., chest pain) and postconcussive (e.g., memory problems) symptoms compared with soldiers who did not screen positive for MTBI. However, after adjusting for PTSD and depression, MTBI was no longer associated with these symptoms, except for headache. These findings suggest that PTSD and related psychiatric conditions such as depression may largely explain the relationship between a positive MTBI screen and physical and postconcussive symptoms 3 to 4 months postdeployment. Postconcussive symptoms associated with MTBI may also affect psychosocial functioning and perceived barriers to healthcare as OEF/OIF veterans readjust to civilian life. In the Hoge et al. (2008) study, a positive MTBI screen was associated with more missed workdays, and PTSD and depression mediated this relation- ship. Research in civilian populations has similarly found that MTBI is associated with psychosocial difficulties, including underemploy- ment, low income, marital problems, and low community integration and life satisfaction, even at 3 years postinjury (Stalnacke, 2007; Vanderploeg et al., 2007). MTBI may also be associated with unmet and unrecognized needs and barriers to receiving help (Pickelsimer et al., 2007). To our knowledge, no published study has yet exam- ined the relationship between MTBI and psychosocial functioning and perceived barriers to care in OEF/OIF veterans, or whether PTSD may mediate this association. The purpose of the current study was to evaluate the preva- lence and comorbidity of MTBI and PTSD in sample of predomi- nantly National Guard/reserve OEF/OIF veterans, and to extend findings of Hoge et al. (2008) by examining whether PTSD may also mediate the relationship between a positive MTBI screen and general health, psychosocial functioning, and perceived barriers to receiving mental healthcare 2 years following return from deploy- ment. Given that loss of consciousness (LOC) may be associated with increased somatic and psychological symptoms (Hoge et al., 2008; Hill et al., 2009), secondary analyses were also conducted to examine whether veterans who screen positive for MTBI with LOC reported greater perceived barriers to care and psychosocial and health dysfunction compared with veterans who screen positive for MTBI without LOC. We hypothesized that MTBI would be associ- ated with increased perceived barriers to care, and psychosocial and health difficulties in bivariate analyses, but that this association would be mediated by PTSD. Further, we expected that respondents with MTBI with LOC would report greater dysfunction compared to respondents with MTBI without LOC. METHOD Sample Participants in this study (N = 277) were drawn from Wave 2 of the Connecticut OEF/OIF Veterans Needs Assessment Survey, which sought to identify salient medical, psychosocial, and eco- nomic needs of this population. OEF/OIF veterans were identified alphabetically from a review of copies of discharge papers (DD- 214s) by the Connecticut Department of Veterans Affairs until names and addresses of 1000 potential respondents were obtained. To maintain confidentiality of the veterans’ names and addresses, surveys were addressed and mailed by the Connecticut Department of Veterans Affairs. No personal identifying information was made available to the authors. The survey was mailed in October 2007 to a sample of 1000 veterans who had served between January 1, 2003 and *Department of Psychiatry, Yale University School of Medicine, New Haven, CT; †National Center for Posttraumatic Stress Disorder, VA Connecticut Health- care System, West Haven, CT; ‡Department of Psychiatry, University of California San Diego School of Medicine, and VA San Diego Healthcare System, San Diego, CA; §Department of Psychology, Central Connecticut State University, New Britain, CT; and Department of Counseling and Family Therapy, Central Connecticut State University, New Britain, CT. Supported by the State of Connecticut, the National Center for PTSD, and a private donation. Send reprint requests to Dr. Robert H. Pietrzak, National Center for PTSD, VA Connecticut Healthcare System, & Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue/151E, West Haven, CT 06516, USA; Phone:860-638-7467; Fax: 203-937-3481; E-mail: robert.pietrzak@ yale.com. Copyright © 2009 by Lippincott Williams & Wilkins ISSN: 0022-3018/09/19710-0748 DOI: 10.1097/NMD.0b013e3181b97a75 The Journal of Nervous and Mental Disease • Volume 197, Number 10, October 2009 748 | www.jonmd.com