As demonstrated in our conceptual model (Figure 2.1), perpetuating factors, such as the use of alcohol to facilitate sleep onset or the use of caffeine or stimulants to increase wakefulness, can contribute to ongoing sleep problems in the post-deployed environment. Several cross-sectional studies indicate that poor health behaviors are associated with an increased risk of sleep problems among servicemember populations (Seelig et al., 2010; Swinkels et al., 2013; Toblin, Clarke-Walper, et al., 2012). For example, a cross-sectional study of Iraq and Afghanistan veterans indicated that long sleep duration (i.e., sleep lasting nine or more hours) was associated with increased odds of smoking (Swinkels et al., 2013). In addition, a large-scale study of more than 41,000 OEF/OIF active-duty servicemembers also found that problem drinking was correlated with trouble sleeping (Seelig et al., 2010). Given that some servicemembers may use alcohol to cope with sleep disturbances (e.g., nightmares or trouble falling asleep), but that chronic or heavy alcohol use can also lead to sleep disturbances, the directionality of these associations remains unclear.
An emerging area of research also suggests that servicemembers may be increasingly using highly caffeinated products, such as energy drinks or "shots" (e.g., Red Bull, Monster, 5-Hour Energy) to compensate for insufficient sleep duration or fatigue. Use of these products may begin in the deployed setting as a way to increase alertness and reduce sleepiness or fatigue. For instance, data from the 2010 Deployment Well Being Survey (J-MHAT 7, 2011) indicated that, of a sample of 998 deployed Army and Marine Corps servicemembers in Afghanistan, 44.8 percent consumed at least one energy drink per day. The nearly 14 percent who were drinking three or more per day reported frequent sleep disruption (Toblin, Clarke-Walper, et al., 2012). The majority of soldiers and Marines in the sample who took sleep medications (60 percent) also drank at least one energy drink per day, suggesting that servicemembers with sleep problems are also more likely to engage in compensatory behaviors to offset sleepiness during the day, compared with those without sleep problems.
Our interviewees also discussed the widespread and frequent heavy use of caffeine, particularly in deployed environments and in the form of energy drinks. According to several interviewees, caffeine use may be so ingrained in military work culture and so routine a part of servicemember recreation that intervening or regulating its use may be difficult. For example,
There is nothing that is going to [diminish] my credibility faster than if I go down range and I say, "Hey, you know you shouldn't really drink all those Rock Stars [energy drinks] and smoke all those cigarettes when you are out on patrol. It's really bad for you, and it's interfering with your sleep." I'm going to get told that, "well, you know that nothing is really going to interfere more with my sleep than getting killed."
Following our conceptual model, consuming caffeine and other energy products may become a habit that perpetuates into the post-deployed setting and has a lasting impact on sleep. Yet, research has just begun to focus on the use of energy products in the post-deployed setting specifically, and the reasons for their use are unclear. For example, Adler et al. (2011) found that approximately one-third of active-duty Army personnel returning from deployments reported an increased use of energy drinks and caffeine since prior to deployment. While the reasons (e.g., to combat fatigue) were not confirmed, the use of these caffeinated products was associated with PTSD symptoms. Although experimental studies show that stimulants, such as caffeine, can promote alertness and performance among sleep-deprived individuals for limited periods, they cannot replace the necessary restorative power of sleep on alertness and performance (Bonnet et al., 2005). Moreover, given the known effects of caffeine on sleep, a vicious cycle can ensue, leading to a perpetuation of sleep problems. That is, a servicemember may consume energy drinks to compensate for sleepiness or fatigue, but particularly when taken later in the day, such consumption can interfere with the quality and duration of sleep, leading to daytime sleepiness and fatigue, and so on.
Although there are few studies in this area with post-deployed servicemember samples, our interviewees and working group participants were particularly informative about these perpetuating factors and how the use of caffeine and stimulants while deployed could continue to affect sleep in the long term. Indeed, misuse of caffeine and energy drinks or other stimulants may serve as a barrier to achieving restful sleep once the opportunity is presented. Regarding the use of energy drinks, one interviewee remarked,
The use is heavy and it's a popular thing to do, part of the culture. We try to discourage it because if they knew better about how to manage their fatigue and got away from the caffeine and got adequate sleep and used the caffeine only when they needed it, I think they would have better success with it, and, in general, I think it's a problem for the military as it is for society.
Sleep medications are the most commonly prescribed psychotropic drug used in theater (Parkinson and Silva, 2011), and our interviewees described the difficultly of extending policies on the use of prescription stimulants and sleep medications. A small number of interviewees raised the point that servicemembers in certain occupational groups—for example, aviation or special forces—regularly use prescription stimulants, or "go pills," to remain alert during long or dangerous missions. However, such use was perceived as a highly regulated practice integral to certain military missions, not as problematic. Some interviewees suggested that the military prescribes the right medications, which produce the desired effect while minimizing the potential for abuse. Still, others discussed the importance of limiting the use of sleeping pills to help with sleep while deployed to ensure that these medications did not impact continuous operations. For example, one interviewee stated,
There are just certain medications we say "no" to because we need you to be alert, or we need you to be at your full mental capabilities almost all the time when you're on the job, and so any prolonged effects from sleeping medications would be inexcusable.
Aside from stimulants, alcohol was perceived to be a notable cause of sleep disturbances, particularly during the post-deployment period, which fits with the research reviewed and the 3P model. Some interviewees highlighted the tendency of certain servicemembers to "self-medicate" with alcohol and to engage in heavy alcohol use after returning from a deployment.
Finally, interviewees also indicated that the overuse of technologies, such as the Internet or video games, which are often used as a means of relaxing and distracting servicemembers from the stress and anxiety of military work, may perpetuate sleep disturbances by increasing arousal right before bedtime. For example, one interviewee noted,
[Servicemembers] have such access now to the Internet, . . . video games, or their music. . . . There's just so many things out there they use to stimulate themselves and try and get their minds off the mission and try and relax. They could do that for hours on end, [and] they end up waking up for the mission exhausted.
Over time, such behaviors may become habitual, which, in turn, can lead to chronic sleep disturbances long after the servicemember has returned from deployment.