As of August 2007, approximately 1.5 million U.S. service members had been deployed to either Iraq (Operation Iraqi Freedom, OIF) or Afghanistan (Operating Enduring Freedom, OEF). The sacrifices of these service members include \>3500 fatalities and \>35,000 injuries resulting in medical air transports. Medical sequelae, such as those involving traumatic amputations and traumatic brain injury, have been common. Contemporary military operations have also been linked to significant adverse mental health consequences. In particular, recent evidence suggests that both overt psychiatric symptoms and other functionally-relevant problems, such as attention and memory impairment, occur. These adverse mental health consequences, already observed in the immediate aftermath of war, could constitute a significant public health problem if prevalent and persistent.
In this context, Cooperative Studies Program (CSP) study #566 proposes an observational cohort design to examine war-related mental health dysfunction beyond the immediate aftermath of war. The proposed work builds on a unique data set available from the Neurocognition Deployment Health Study (NDHS), an interagency collaboration between the Department of Defense (DoD) and the Department of Veterans Affairs (VA). Initiated in April 2003, with an initial enrollment of 1595 participants, the NDHS has focused on short-term mental health outcomes of OIF deployment. To date, the NDHS is the only deployment health study of U.S. troops that includes both prospectively-gathered pre-deployment (baseline) and post-deployment (within 90 days after return from the war) data, as well as objective, performance-based measures of mental functioning.
The proposed work would collect new "long-term follow-up" data 3 to 5 years after NDHS participants returned from their initial deployment to Iraq. The newly acquired data from the proposed work will be analyzed with data available from the previous waves of the NDHS. The two primary objectives of CSP #566 are to: (1) determine the prevalence and course of posttraumatic stress disorder (PTSD) among Iraq War Veterans 3-5 years following return from their Iraq War deployment; and (2) assess the persistence of previously observed neuropsychological changes (in attention, verbal learning, visual memory, and reaction time) following war-zone participation and their relationships to the subsequent development of PTSD as the end-point. The second primary objective also evaluates traumatic brain injury (TBI) as a possible neural risk factor for PTSD.
The two secondary objectives are to: (1) examine the association of risk and resilience factors, including the impact of war zone stressors, with the outcomes of PTSD, major depressive disorder (MDD), and panic disorder; and (2) determine whether changes in PTSD symptoms or neuropsychological function are associated with subsequent day-to-day functioning, including health-related functional activities and occupational functioning.
The proposed study includes two hierarchical participant sampling frames: (1) a "full sample" (N=817) for examination of PTSD and related outcomes; and (2) a "neuropsychological subsample" (N=200) for examination of neuropsychological and functional outcomes. Both samples are drawn from the anticipated 1149 participants from the original NDHS cohort who deployed to Iraq and consented to be contacted for future research. The "full sample" component includes clinician-administered structured psychiatric phone interviews to determine clinically significant cases of PTSD, major depressive disorder, and panic disorder; a mail questionnaire survey will provide assessment of posttraumatic stress (PTS) symptom severity. The "neuropsychological sample" component includes in-person performance-based assessment of neuropsychological outcomes, shown previously to be affected by deployment to Iraq. In addition, participants in the neuropsychological sample will complete questionnaires relevant to health-related functional impact and occupational functioning.
The planned duration of the study is 5.5 years, including a 6 month start-up period, 42 months to locate, contact, and complete assessments on participants, 6 months to lock and close the database, and 12 months to complete the primary and secondary analyses. The attributes of the established study population, in combination with the scope of the proposed work, offer a unique opportunity to answer scientific questions with direct relevance to healthcare policy for returning OIF Veterans. Specifically, this study can 1) identify quantifiable and objective measures associated with subsequent outcome and functioning, 2) determine early potentially modifiable factors that may be used to promote resilience, 3) optimize treatment "windows," and 4) help project future resource allocation based on the frequency and impact of the mental health problems identified.
