... Additionally, of the approximately 10% of those exposed to trauma who develop posttraumatic stress disorder (PTSD; Kilpatrick et al., 2013), 70-87% have trouble initiating or maintaining sleep or experience nightmares, making sleep difficulties the most highly reported PTSD symptom (Maher, Rego, & Asnis, 2006). Sleep difficulties commonly occur immediately after trauma exposure (Wood, Bootzin, Rosenhan, Nolen-Hoeksema, & Jourden, 1992) and may persist long after the trauma (> 45 years later, Goldstein, van Kammen, Shelly, Miller, & van Kammen, 1987;Rosen, Reynolds, Yeager, Houck, & Hurwitz, 1991). Further, sleep difficulties in trauma-exposed populations can arise indirectly from other issues resulting from trauma, such as depression or anxiety (e.g., Sheikh, Woodward, & Leskin, 2003), substance abuse (e.g., Stewart, Pihl, Conrod, & Dongier, 1998), and cardiometabolic dysfunction (e.g., Heppner et al., 2009;Vgontzas, Bixler, & Chrousos, 2005). ...