Mental health screening of soldiers prior to deployment to a theater of war was first attempted by the U.S. Army in World War I in the hope of avoiding the high rates of psychiatric casualties observed in British and French troops, but it did not prevent extensive disability from shell shock in American World War I veterans (1). In World War II, the U.S. military carried out mass neuropsychiatric screening with the aim of identifying individuals who might be psychologically vulnerable to later psychiatric breakdown in the combat environment because of, for example, neuroses or minor personality defects (1). In World War II, as in later wars, predeployment screening to predict the development of future mental disorders was a failure for a variety of reasons, including imprecise screening methods and instruments, poor interrater reliability, high false positive rates, low thresholds for caseness that did not discern significant severity, and low predictive power (1).

A different form of predeployment mental health screening is that which screens for existing, rather than future, psychiatric disorders for purposes of psychiatric referral, surveillance, treatment, or discharge due to the severity or instability of the disorder (1). The U.S. military has gradually built mental health screening practices on this approach. In 1998, the U.S. Department of Defense introduced the 8-item self-report Pre-Deployment Health Assessment (PreDHA), which remains mandatory. A single question specifically addresses mental health: "During the past year, have you sought counseling or care for your mental health?" The form is reviewed with a primary care provider who determines whether referral is indicated (2). The PreDHA was unevaluated until 2007, when it was shown to have low validity, identifying less than half of the 4.2% of soldiers with a clinical record of psychiatric diagnosis within the year preceding their deployment to Afghanistan (2).

In 2006, concern that mentally unfit soldiers were being deployed to Iraq and Afghanistan led to a Congressional mandate for enhanced mental health screening. As a result, the Department of Defense issued a policy that specified criteria for deployment-limiting diagnoses (psychotic and bipolar disorders), medications (e.g., lithium), instability, and functional severity (3). The procedure by which health care providers conducting the screening were to operationalize the criteria was ill-defined, with practices varying across sites (4). U.S. military predeployment mental health screening has occurred on a large scale with minimal evaluation of its efficacy. Based on U.S. armed forces data (5), predeployment health assessments ranged from some 12,000 to 110,000 monthly since January 2003, averaging 34,774 per month in 2010.

The study by Warner et al. in this issue (6) makes two important contributions to our understanding of the effects and potential of predeployment mental health screening. First, it is the first study to evaluate the effectiveness of predeployment screening for psychiatric disorders for a modern military combat setting, and specifically for U.S. troops in Iraq. Second, the authors show how a clear protocol can systematically link predeployment screening with care coordination, integrated from predeployment to deployment settings, to reduce significant negative mental health outcomes in deployed soldiers. As implementation of the 2006 Department of Defense policy was uneven across brigades because of their rapid deployment during the 2007 surge of forces into Iraq, the authors took the opportunity to compare the effects of two forms of predeployment mental health assessment on dysfunctional outcomes during deployment: PreDHA assessment alone versus the PreDHA plus their predeployment mental health screen operationalizing the 2006 policy criteria (3) with coordinated care during deployment. Using a cohort design, the authors compared 10,678 soldiers from three brigades screened prior to deployment with 10,353 soldiers from three brigades that were not screened prior to deployment. The authors measured outcomes during deployment in Iraq that indicated significant dysfunction: seeking mental health services for combat stress, psychiatric disorders, or suicidal ideation; being placed on occupational duty restrictions (e.g., short-term weapons restrictions); and air evacuation from theater for behavioral health problems.

In the predeployment setting, the authors' screening protocol resulted in 7.7% of soldiers being referred for mental health evaluation-substantially more than the 0.3% referral rate from standard PreDHA screening of soldiers deployed to Afghanistan (2) and the 1.3% referral rate of U.S. Army soldiers screened in 2009 and 2010 with the PreDHA under 2006 Department of Defense guidelines (5). Mental health evaluation resulted in only 0.7% of screened soldiers not being cleared to deploy because of deployment-limiting diagnoses or medications. Among the screened soldiers, 7.0% were identified as having mental health needs and received a care plan for continuity of care while deployed in Iraq. Medication and monitoring during deployment were done predominantly by primary care providers with consultation and tracking by mental health specialists in a collaborative care model. Negative outcomes were significantly less frequent in the screened than in the unscreened brigades during 6 months of deployment.

One limitation of the study is that the authors relied on self-report to identify soldiers with psychiatric diagnoses or treatment. Stigma and barriers to mental health care in the military inhibit self-reporting and help-seeking (7) and very likely caused underdetection by the authors' screening. Second, the beneficial effects of identifying soldiers with psychiatric disorders at screening might dissipate beyond the study's 6-month span, given that rates of mental disorders in military populations increase with greater exposure to combat and with duration of deployment (7). Third, the study's outcome measures were not actual rates of mental disorders or symptoms in deployed troops. For example, the authors' reported rate of soldiers seeking care for suicidal ideation (0.4% of screened soldiers compared with 0.9% of unscreened soldiers) is based on a particular manifestation of suicidality and not the actual rate of suicidal ideation in troops (15.8% of surveyed soldiers in Iraq reported suicidal ideation within the previous 4 weeks in 2007 [7]). A fourth limitation of the study is its observational design. A randomized controlled trial would be ideal for future studies of screening efficacy. Strengths of the study are its 100% response rate, the standardized tracking system to monitor outcomes, and the large sample size, which allows evaluation of important but uncommon outcomes (e.g., air evacuation).

It is important to keep in mind that this study does not show that more detailed mental health screening itself improves outcomes. The screening was not tested on its own but was linked to proactive, improved coordination of care in the deployed setting. U.S. soldiers with mental health problems in Iraq and Afghanistan report significant stigma and barriers to care, particularly soldiers in forward combat zones (7, 8). Warner and colleagues' study implies the possibility that stigma, barriers to care, and relapse may be lessened and symptoms and medication continuity improved if soldiers with mental disorders enter their deployment already linked to treatment with a care provider.

Recent changes in U.S. military policies and programs are promising for integrated mental health screening and care. A 2010 Department of Defense policy expands mental health screening and surveillance (9). Collaborative mental health care is the basis of the RESPECT-Mil program for depression and posttraumatic stress disorder (10) and the forthcoming Comprehensive Behavioral Health System of Care (11). It is incumbent on the U.S. military to prospectively evaluate these new programs in order to provide high-quality evidence-based systems for supporting soldiers in the field, as well as for soldiers who have returned to their base or home.