A Conceptual Model of Post-Deployment Sleep Problems
To provide a conceptual framework for understanding deployment-related sleep problems and to guide the literature review, we drew from an influential model of insomnia developed by Spielman and colleagues (Spielman, Caruso, and Glovinsky, 1987; Spielman and Glovinsky, 1991). Researchers have recently adapted the model to focus on sleep problems that are relevant to military populations (Bramoweth and Germain, 2013). We further refined this model for our framework, as shown in Figure 2.1. We consider this framework to be particularly valuable for considering how sleep problems persist into the post-deployment period, given that more than 2 million servicemembers have deployed to combat arenas in response to the wars in Iraq and Afghanistan over the past 13 years and that sleep problems have emerged as a major concern among these servicemembers after deployment (DCoE, 2012; Schmitz, Browning, and Webb-Murphy, 2009; Young-McCaughan, Peterson, and Bingham, 2011).
According to Spielman's original 3P model (Spielman, Caruso, and Glovinsky, 1987; Spielman and Glovinsky, 1991),predisposing factors are stable or enduring characteristics (e.g., anxious temperament, gender) that increase one's vulnerability to developing insomnia. Precipitating factors are situations or events that trigger the initiation
Figure 2.1. Adaptation of Spielman's 3P Model to Understand Post-Deployment Sleep Problems Among Servicemembers
SOURCES: Adapted from Spielman, Caruso, and Glovinsky, 1987, and Spielman and Glovinsky, 1991.
of insomnia and may include major life events (e.g., divorce, death of a loved one), psychological or environmental factors (e.g., work-related stress, change to a new location with an adverse sleeping environment), or medical factors (e.g., illness, new medication). Predisposing and precipitating factors are similar to those in a diathesis-stress model, in which vulnerability interacts with environmental stressors to lead to the manifestation of a clinical disorder (Ingram and Luxton, 2005). Predisposing and precipitating factors are often not amenable to change. However, perpetuating factors are often modifiable thoughts or behaviors and, thus, represent potential targets for behavioral intervention. Specifically, Spielman posits that to cope with acute sleep disturbances, individuals often develop compensatory behaviors (e.g., spending more time in bed, taking naps, using caffeine or stimulants to stay awake during the day, worrying about daytime consequences if they cannot get a good night's sleep), which ultimately serve to perpetuate the sleep disturbance.
Longitudinal research with civilians has supported the 3P model of insomnia. For example, such factors as a family history of insomnia, genetic susceptibility, and anxious temperament can serve as predisposing factors for sleep problems (LeBlanc et al., 2009; Drake, Friedman, et al., 2011). Precipitating events, like adverse childhood experiences and severe illness, have also been shown in longitudinal studies to contribute to insomnia (Healey et al., 1981; Gregory et al., 2006). Perpetuating factors, like the use of alcohol to fall asleep or the use of daytime caffeine to combat sleepiness, may help in the short term but are linked to long-term sleep problems (Roehrs and Roth, 2001; Aurora et al., 2012; Bonnet and Arand, 1992; Bonnet et al., 2005). Predisposing factors and precipitating factors, such as stressful events, have been shown to combine to contribute to a greater risk of developing insomnia (Morin, Rodrigue, and Ivers, 2003), and predisposing factors may exacerbate the effects of perpetuating factors on poor sleep (e.g., physiological reaction to caffeine; Bonnet and Arand, 2003).