Research Brief

The Health Related Behaviors Survey (HRBS) is the U.S. Department of Defense's (DoD's) flagship survey for understanding the health, health-related behaviors, and well-being of service members. Fielded periodically for more than 30 years, the HRBS includes content areas that might affect military readiness or the ability to meet the demands of military life. The Defense Health Agency asked the RAND Corporation to revise and field the 2018 HRBS among members of both the active component and the reserve component. This brief discusses findings for the active component.

In this brief, results for deployment experiences and health are reviewed. Some results are also compared with Healthy People 2020 (HP2020) objectives established by the U.S. Department of Health and Human Services for the general U.S. population. Because the military differs notably from the general population (for example, service members are more likely to be young and male than is the general population), these comparisons are offered only as a benchmark of interest.

Frequency and Duration of Deployments

The 2018 HRBS included several questions asking respondents about their deployment experiences. These included the number of times respondents had been deployed and length of and experiences on deployments.

Across all services, 60.4 percent (confidence interval [CI]: 59.2–61.7) of respondents reported having had at least one previous deployment, including both combat and noncombat deployments. Navy respondents were most likely to report ever having deployed. Most personnel who had deployed had done so multiple times, with 28.4 percent (CI: 27.5–29.3) having deployed at least three times. Coast Guard personnel were most likely to report having deployed at least three times (Figure 1).

Figure 1. Lifetime Number of Deployments, by Service Branch

Zero One Two Three or more
Total 39.6% 19.3% 12.7% 28.4%
Air Force 45.0% 19.7% 11.6% 23.7%
Army 42.1% 19.4% 12.6% 26.0%
Marine Corps 43.3% 22.3% 11.8% 22.8%
Navy 28.3% 18.7% 15.5% 37.5%
Coast Guard 41.4% 7.5% 5.0% 46.1%

Among those who had deployed, total lifetime duration of deployments varied widely. At one end, 18.1 percent (CI: 16.9–19.3) had deployed for no more than six months; at the other, 11.2 percent (CI: 10.6–11.9) had deployed for more than 48 months. Overall, 50.1 percent (CI: 48.8–51.5) of those who had ever deployed had done so for a total of seven to 24 months. Air Force and Marine Corps personnel were the most likely to report lifetime duration of deployments of no more than six months. Army, Navy, and Coast Guard personnel were the most likely to report lifetime duration of deployments of more than 48 months (Figure 2).

Figure 2. Lifetime Duration of Deployments Among Those Who Have Deployed, by Service Branch

1 to 6 months 7 to 12 months 13 to 24 months 25 to 48 months 49 months or more
Total 18.1% 26.2% 24.0% 20.5% 11.2%
Air Force 28.1% 26.5% 25.4% 14.8% 5.3%
Army 10.9% 27.9% 22.0% 25.7% 13.6%
Marine Corps 28.7% 22.3% 23.2% 17.4% 8.4%
Navy 14.0% 26.6% 25.5% 20.4% 13.6%
Coast Guard 19.5% 19.0% 24.1% 20.5% 16.9%

Among those who had deployed, 54.3 percent (CI: 52.9–55.7) had not done so in the past year. Air Force personnel were most likely to report not having deployed in the past year.

Combat Deployments

Those who had deployed also differed in their experience with combat deployments. Among all who had deployed, 72.7 percent (CI: 71.3–74.0) had at least one combat deployment. Members of the Coast Guard who had deployed were the least likely to have had a combat deployment, while those of the Air Force and Army were the most likely to have had at least three combat deployments (Figure 3).

Figure 3. Number of Combat Deployments Among Those Who Have Deployed, by Service Branch

Zero One Two Three or more
Total 27.3% 31.8% 17.9% 23.0%
Air Force 22.5% 34.9% 18.7% 23.9%
Army 15.1% 35.5% 19.6% 29.9%
Marine Corps 44.2% 23.8% 15.5% 16.5%
Navy 32.4% 30.5% 17.6% 19.5%
Coast Guard 73.8% 17.7% 5.4% 3.0%

Among all who had deployed, 36.2 percent (CI: 34.9–37.5) reported a traumatic combat experience, such as working with landmines, witnessing members of their unit or an ally unit being seriously wounded or killed, or being wounded in combat at some point in their deployments. Army personnel (57.5 percent, CI: 54.5–60.4) were more likely than those of the other services to report any combat trauma exposure. The four most commonly reported traumatic combat experiences were knowing well someone who was killed in combat (22.3 percent, CI: 21.2–23.3), witnessing members of one's own unit or an ally unit being seriously wounded or killed (21.0 percent, CI: 20.0–22.0), witnessing civilians being seriously wounded or killed (18.9 percent, CI: 17.9–19.9), and working with landmines or other unexploded ordnance (10.5 percent, CI: 9.6–11.3).

Deployment and Substance Use

Those who had deployed in the past 12 months (recent deployers) differed from those who had not deployed in that time in their drinking, smoking, and marijuana use. Specifically:

  • 39.8 percent (CI: 37.5–42.2) of recent deployers reported binge drinking (consumption of at least five drinks by men or four drinks by women on the same occasion in the past 30 days), compared with 31.8 percent (CI: 30.5–33.2) of non–recent deployers.
  • 12.6 percent (CI: 10.9–14.4) of recent deployers reported heavy drinking (binge drinking at least once each week during the past 30 days), compared with 8.7 percent (CI: 7.9–9.6) of non–recent deployers.
  • 22.4 percent (CI: 20.2–24.5) of recent deployers reported cigarette smoking in the past 30 days, compared with 16.8 percent (CI: 15.7–18.0) of non–recent deployers.
  • 0.7 percent (CI: 0.03–1.4) of recent deployers reported any marijuana or synthetic cannabis use in the past 30 days, compared with 0.2 percent (CI: 0.1–0.3) of non–recent deployers.

Recent deployers and non–recent deployers did not differ significantly in their e-cigarette use; in substance use (excluding marijuana); and in misuse of prescription drugs, stimulants, sedatives, and pain relievers.

Deployment and Mental and Emotional Health

The HRBS asked respondents about a variety of mental health indicators. It assessed overall mental health status using the Kessler-6 (K6), a commonly used measure of nonspecific serious psychological distress. The K6 is designed to distinguish between distress that indicates the presence of a psychiatric disorder that a clinician would recognize and treat and distress that is commonly experienced but not suggestive of a clinical condition. The HRBS also included items to indicate probable posttraumatic stress disorder (PTSD) and items on sleep quality.

Recent deployers (68.3 percent, CI: 66.0–70.6) were less likely than non–recent deployers (71.2 percent, CI: 66.9–72.6) to indicate no to low distress in the past 12 months on the K6. They were also more likely (14.6 percent, CI: 12.8–16.4) than non–recent deployers (12.6 percent, CI: 11.6–13.5) to indicate moderate distress in the past 12 months.

The difference between the two groups in levels of serious distress in the past 12 months, however, was not significant. Furthermore, recent deployers did not differ significantly from non–recent deployers in psychological distress over the past 30 days, probable PTSD, or sleep quality.

Deployment and Physical Health

The HRBS asked whether respondents had any bodily pain symptoms in the past 30 days, asked whether they had any indicators of traumatic brain injury in the past 12 months or postconcussive symptoms in the past 30 days, and asked them to provide self-ratings of health. For all of these, there were no significant differences between recent deployers and others. (For more information on physical health characteristics of the overall force, see the brief on physical health and functional limitations for the active component.)


The HRBS provides insight on how deployment is associated with active component service members' physical and mental health outcomes and propensity for risk behaviors. Understanding this association is important given that service members often deploy more than once in their careers, and that the negative consequences for health and health behaviors that result from one deployment could impact readiness for future deployments.

Most 2018 HRBS respondents had experienced at least one deployment since joining the military. Exposure to combat trauma was also common. Problematic alcohol use, cigarette smoking, and marijuana use were more common among those who had recently deployed. Use of other drugs and prescription drug misuse was far less common, with no difference between recent deployers and non–recent deployers.

Recent deployers were also less likely to report no psychological distress in the past 12 months and more likely to indicate moderate distress in that time. They were no more than likely than others, however, to indicate severe distress in that time. They also did not differ from others in levels of distress over the past 30 days, probable PTSD, sleep quality, bodily pain symptoms, postconcussive symptoms, or self-ratings of health.


  • [1] CIs provide a range in which the true population value is expected to fall. They account for sampling variability when calculating point estimates but do not account for problems with question wording, response bias, or other methodological issues that, if present in the HRBS, might bias point estimates.

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