zone stressors, or even deployment itself can have immediate and long-term physical, psychologic, and other adverse consequences. Some of the consequences have been generally constant throughout the history of warfare, even though the context and nature of warfare have changed dramatically. However, throughout history, society and culture have played a powerful role in how the effects of war on soldiers have been viewed, in the perceived nature and causes of the effects, and in how soldiers were treated for them. Although the experiences of those deployed to Iraq or Afghanistan bear similarities to the experiences of those deployed in previous conflicts, there are a number of distinctive and important differences in who is serving, how they are deployed, and how the conflicts are being fought. The differences have important consequences for the types and severity of challenges and readjustment problems likely to be experienced by the men and women serving in OEF and OIF and for the types of support that they and their families need both in theater and on their return home. Most of the differences are notable in that our armed forces and our country as a whole have not had relevant experience with the key features of organization and warfare that make these conflicts most distinctive. Furthermore, the research that has been conducted shares a set of limitations with studies of the experiences in prior conflicts. Those limitations include
Reliance on samples of convenience, which limits their external validity (generalizability).
Reliance on brief screening instruments to identify key outcomes and to estimate prevalence, which limits internal validity.
Use of cross-sectional designs, which limits the ability to support causal inference and to elucidate the course of disorders.
Assessment of narrow sets of risk and protective factors, which results in under-specified models with a high risk of bias.
Conduct of many studies by VA or DOD, rather than by independent third parties, which raises important questions about the accuracy of respondents’ self-reports, particularly with regard to sensitive issues.
All those limitations are understandable given the fiscal and practical challenges involved in conducting long-term outcome studies (for example, longitudinal epidemiologic studies are expensive and difficult to implement). To be useful in the formulation of policy, however, studies need to be both scientifically sound and comprehensive. The committee is aware of the Millennium Cohort Study, several studies being conducted by RAND, and other studies that are in progress. Additional studies that address some of the methodologic challenges identified above—for instance, using probability sampling, diagnostic interviewing, and longitudinal designs—will be needed to move the field forward.
The committee recommends that the Department of Defense, the Department of Veterans Affairs, and other federal agencies fund research on readjustment needs of returning OEF and OIF veterans, their families, and their communities that explicitly addresses methodologic and substantive gaps in completed and ongoing research. For example, the support of large-scale, independent studies with longitudinal designs, probability sampling, comprehensive clinical assessment of key outcomes, and more fully specified models that include objective biologic measures should be considered.
In Chapter 4, the committee presents many of its preliminary findings and notes that research and program development are needed to substantiate the potential efficacy and cost