Alcohol misuse has been among the concerns reported by soldiers returning from deployment,10
yet research to date has not been able to quantify the relationship between alcohol problems and deployment. To our knowledge, this is the first study to prospectively investigate alcohol misuse in relation to deployment using 3 different metrics in a large population-based military cohort of both active-duty and Reserve/Guard personnel by documenting alcohol use patterns before and after deployment related to the wars in Iraq and Afghanistan. This study found a significantly increased risk for new-onset heavy weekly drinking, binge drinking, and other alcohol-related problems among Reserve/Guard personnel deployed with reported combat exposures compared with nondeployed Reserve/Guard personnel.
Increased alcohol outcomes among Reserve/Guard personnel deployed with combat exposures is concerning in light of increased reliance on Reserve/Guard forces supporting current operational requirements. This finding is consistent with a recently published study of soldiers returning from Iraq, in which endorsement of alcohol problems according to a 2-item alcohol screen in the newly implemented Post-Deployment Health Reassessment was reported to be 11.8% for active duty and 15.0% for Reserve/Guard.10
A study examining the baseline prevalence of mental health in the Millennium Cohort showed that the weighted prevalence of alcohol-related problems, defined as endorsing one of 5 Patient Health Questionnaire measures, was lower in regular active-duty members (11.5%) compared with Reserve/Guard members (14.1%).61
Possible explanations for increased risk for new-onset drinking outcomes in Reserve/Guard members after deployment include inadequate training and preparation of civilian soldiers for the added stresses of combat exposures faced during deployment; increased stress among individuals and their families having to transition between military and civilian occupational settings; military unit cohesiveness; and reduced access to support services, including family services, health and physical fitness programs, and ongoing prevention programs in civilian communities.10,62
Other demographic and military characteristics associated with changes in drinking behavior include younger age, sex, race/ethnicity, and service branch. Increased risk for alcohol problems in younger personnel is not surprising when it is compared with that of other young cohorts and reported high binge-drinking levels.63
Interventions focused on drinking reduction in younger cohorts that have been effective should be considered in young military personnel before, during, and after deployment. Women were significantly more likely to start drinking heavily but less likely to start binge drinking or have alcohol-related problems compared with men, which may be due to women turning to drinking as a coping mechanism, whereas men may have a higher propensity for risk-taking behaviors.64,65
Sex-specific educational programs for interventions to reduce drinking may be considered. Our finding that whites were at increased risk for drinking outcomes compared with blacks or other races is consistent with past research.38,41,42
Active-duty Marines were also found to be at increased odds of continuing to binge drink after deployment, as well as to experience new-onset alcohol-related problems. Marines may represent another group that should be targeted for interventions because the Hoge et al9
study also showed a higher likelihood of alcohol misuse among Marines than Army personnel after deployment.
Individuals with previous mental health or alcohol problems were at significantly increased risk for changes in drinking behavior. Among CAGE/alcohol-positive individuals at baseline, risk for new-onset and continued drinking at follow-up was high for all 3 outcomes, potentially representing vulnerability toward drinking in these individuals. Those with baseline symptoms of depression or PTSD and depression were also at increased risk for new-onset alcohol-related problems in active duty and Reserve/Guard. Among Reserve/Guard, the risk for new-onset alcohol-related problems was significant for those with any report of mental health symptoms or medication use, possibly because of the difficulties of work and family responsibilities that shift quickly. Research has suggested that PTSD is associated with changes in alcohol consumption5
and that alcohol misuse is comorbid with several mental health disorders.56
However, it is difficult to separate any clear causal pathways because the etiology of these disorders is likely intertwined.
Unfortunately, a simple solution to mitigating the effects of these comorbidities among military personnel has yet to be discovered, and research has identified difficulties in reducing stigma and barriers to care.8–10
A recent report showed that although the military has reduced smoking and other drug use, progress remains slow on reduction in heavy drinking.66
Continued screening using such items as the Post-Deployment Health Reassessment, given 3 to 6 months after deployment, will help to identify at-risk individuals who may need to seek treatment. As Milliken et al10
suggested, it is important that the military establish policies endorsing “confidentiality” and “self-referral” for optimal effectiveness. A potentially interesting strategy to aid problem drinkers is self-help, Web-based intervention.67
This method was tested in a controlled trial, showed efficacy in drinking reduction, and could be promising for use among military personnel because of perceived privacy of a Web-based tool. Another potential strategy to reduce drinking involves assessing “drinking motivation type (experimenters, thrill seekers, multireasoners, and relaxers)” and then targeting interventions according to a person’s profile.68
Finally, a technique called the brief negotiated interview, proposed by Fernandez et al,69
uses a “method designed to enhance a patient’s motivation to change, rooted in the principles of motivational interviewing.” This method might be useful for the military in settings in which one-on-one interaction is feasible because development of rapport with the individual is a key to this method.
Our study has several possible limitations. The Millennium Cohort may not be representative of the military as a whole or those who are deployed. However, thorough evaluations of possible biases suggest the cohort is a representative sample of military personnel, as measured by demographic and mental health characteristics and reliable health and exposure reporting.18,61,70–74
Nondeployed individuals may not have deployed because they were unfit owing to health status, which means our comparison group may have been less healthy than our deployed groups, potentially biasing our results toward the null. Another important limitation is that the authors did not collect information on the circumstances under which the participants took the survey. Therefore, the various circumstances under which responses were reported, such as anxiety before war, may have influenced response. However, because both binge drinking and alcohol-related problems were related to behaviors during the past year, the effect of differing circumstances was likely minimal. Additionally, the average amount of time between returning home from deployment and completing the follow-up survey was 1 year, making it difficult to determine both short- and long-term effects of deployment on alcohol use. Self-reported data are subject to recall bias, and the actual number of drinks consumed in the past week may be difficult for participants to easily remember.75,76
Measures of binge drinking also differed slightly between baseline and follow-up assessments. Although the core text of the questions (“5 or more drinks” in 1 day or on 1 occasion) was nearly identical, the response options were presented differently. Another potential limitation is that both questionnaires identify overall alcohol consumption, which has been shown to underestimate actual consumption compared with beverage-specific consumption questions.75
It is also possible that military personnel are less likely to endorse alcohol-related questions because of concern that acknowledging risky behavior could hinder career progression. However, other studies have found that self-reported weekly alcohol consumption measures, even when service members know the survey is not anonymous, demonstrate good criterion-related validity.31
Finally, although we collected data on several known and theoretical confounders, we did not have information on other drug use.
Despite these limitations, our study has important strengths. The Millennium Cohort has the advantage of being systematically drawn from all branches and components of the US military, yielding a large sample size with statistical power to detect meaningful differences among subgroups of this population. Additionally, data on quantity of drinking are strengthened by the use of different metrics (weekly drinking, daily drinking, and alcohol problems) to capture this information. Moreover, these data longitudinally measure heavy drinking, binge drinking, and drinking-related problems, independent of the timing of deployment, providing prospective insight into these outcomes and any relationship to military deployment in a large population-based sample. Further, alcohol use has been suggested as one possible explanation for previously unexplained increases in injury mortality subsequent to deployment.77
Finally, although self-reported alcohol consumption may not be a perfect measure, other epidemiologic studies have found these measurements to be generally reliable.78,79
In conclusion, our study found that combat deployment in support of the wars in Iraq and Afghanistan was significantly associated with new-onset heavy weekly drinking, binge drinking, and other alcohol-related problems among Reserve/Guard and younger personnel after return from deployment. These results are the first to prospectively quantify changes in alcohol use in relation to recent combat deployments. Interventions should focus on at-risk groups, including Reserve/Guard personnel, younger individuals, and those with previous or existing mental health disorders. Further prospective analyses using Millennium Cohort data will evaluate timing, duration, and comorbidity of alcohol misuse and other-alcohol related problems, better defining the long-term effect of military combat deployments on these important health outcomes.