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Acute behavioral health crises are one of the leading causes of medical evacuation from combat operations for American service members (Williams, Stahlman, & Oh, 2017), and evacuees with psychiatric disorders are less likely to return to duty (Cohen, et al., 2010). In addition to the $100,000 estimated cost per evacuation (Weber & Weber, 2015), each evacuation inflicts substantial disruption for the service member and their combat unit.
Service members complete health screenings prior to deployment, which include screenings and – if indicated – follow-up assessment for symptoms of depression, posttraumatic stress disorder (PTSD), alcohol use disorder (AUD), suicidal ideation, and violence risk. The predictive validity of such screenings has not been well-studied. While the military recognizes that service members have behavioral health needs while deployed and ensures that behavioral health clinicians and nonclinical support are available in theater, unit leaders do not know which service members are more likely to benefit from these types of assistance or which type of support and associated personnel could be most beneficial to the unit as a whole. Therefore, we set out to determine variables that may help predict which service members are more likely to be medically evacuated from theater for behavioral health concerns.

We examined administrative data on over 600,000 service members deployed to Iraq and Afghanistan over a six-year period. Using logistical regression analyses, we developed and then tested a model for predicting behavioral health evacuations from theater. Based on the predictive strength of each predictor variable in the logistic regression analysis, we developed a tool that assigns behavioral health evacuation risk scores to deploying service members. Providers or unit leaders select values for 11 variables (pre-deployment behavioral health screening scores for PTSD, depression and AUD, age, gender, marital and parental status, military branch and rank, number of prior deployments, prior behavioral health diagnoses) to obtain a risk score and associated risk-level category (minimal, low, medium, or high) for each potential deployer. This is a prototype tool that can be utilized by line leadership to assess the impact of deployment on Service members with particular risk profiles. The tool also educates primary care providers about the predictive validity of pre-deployment health screening and gives providers more information to determine follow-up referrals when service members screen positive on behavioral health measures.

While we believe this tool will be useful to unit leaders and providers, we also recognize the potential pitfalls of distributing such a tool widely without proper training on its use. For instance, knowing that women are statistically more likely than men to be evacuated for behavioral health reasons could foster a belief that female service members are more vulnerable than their male counterparts by mere virtue of their gender, rather than understanding and addressing how women’s experiences in the military are different than men’s, such as greater risk of sexual assault and harassment during and prior to military service (Kimerling et al., 2010) and lower perceived unit cohesion (Carter-Visscher et al., 2010). This knowledge can also help unit leaders develop mitigation interventions, such as ensuring women are deployed in positions of leadership and as Combat and Operational Stress Control providers.

User training also needs to emphasize that risk factors are based on population estimates, and the presence of multiple risk factors should not be used to infer risk in any single individual. Rather, the tool emphasizes the need for follow-up evaluation through referral to specialty care or primary care behavioral health consultants. There, individual recommendations can be developed for clinical and nonclinical support in the deployed setting, or delay of deployment until the service member is more medically ready.

A potential future direction for this research is strengthening the predictive model with inclusion of other potential risk factors, such as previous combat exposure, lengths of deployments, pre-enlistment waivers, and military occupation. The methodology used in our study may also be applied to other outcomes, such as early attrition from the military, medical discharges, behavioral infractions, or non-behavioral health evacuations.


Carter-Visscher, R., Polusny, M.A., Murdoch, M., Thuras, P., Erbes, C.R., & Kehle, S.M. (2010). Predeployment gender differences in stressors and mental health among U.S. National Guard troops poised for Operation Iraqi Freedom deployment. Journal of Trauma Stress, 23, 78-85.

Cohen, S.P, Brown, C., Kurihara, C., Plunkett, A., Nguyen, C., & Strassels, S.A. (2010). Diagnoses and factors associated with medical evacuation and return to duty for service members participating in Operation Iraqi Freedom or Operation Enduring Freedom: A prospective cohort study. The Lancet, 375, 301-309.

Kimerling, R., Street, A.E., Pavao, J., Smith, M.W., Cronkite, R.C., Holmes, T.H., & Frayne, S.M. (2010). Military-related sexual trauma among Veterans Health Administration patients returning from Afghanistan and Iraq. American Journal of Public Health, 100(8), 1409-1412.

Weber, E., & Weber, D.K. (2015). Deployment limiting mental health conditions in US military personnel deployed to combat theaters: predictors of theater mental health evacuation. Journal of Psychology and Clinical Psychiatry, 2(4), 1-5.

Williams, V.F., Stahlman, S., & Oh, G.T. (2017). Medical evacuations, Active and Reserve components, U.S. Armed Forces, 2013-2015. Medical Surveillance Monthly Report, 24(2), 15-21.

Reference Article

Thornquist, M.H., Leonard, J.E., Fraine, M.C., Loftis, C.W., & Davison, J.W. (2019). Development of a Tool to Predict Risk of Behavioral Health Evacuation from Combat. Journal of Traumatic Stress.

Discussion Questions

  1. Could the development and use of a tool such as the one described here result in stigmatization of those with certain characteristics that convey higher risk? If so, what can be done to mitigate the potential for stigmatization?
  2. Why do you think behavioral health disorders are one of the most common categories of illness related to medical evacuation from theater?

Author Biographies

Mary Thornquist, PhD, is a clinical psychologist with SAIC and provides consultation on behavioral health issues to the Defense Health Agency.

James Leonard MPH, is an epidemiologist and biostatistician with EH Tools, Inc. and provides consultation on military health data, statistics, and study design to the Defense Health Agency, among other clients.

Melissa Fraine, MPH, is an epidemiologist with Salient CRGT and provides consultation to the Defense Health Agency, Psychological Health Center of Excellence.

Christopher Loftis, PhD, is a clinical psychologist with National Director for VA/DoD Mental Health Collaboration for the Department of Veterans Affairs.

John Davison, MBA, PhD, is a clinical psychologist with the Office of the Deputy Assistant Director for Medical Affairs at the Defense Health Agency.