“…Similarly, PO dependent individuals exhibited self-reported sleep disturbance (assessed by the PSQI) and sub-threshold insomnia (assessed by the ISI) that were approximately 10 and 4.5 times higher, respectively, than controls. In accordance with these findings, prior research has documented deficits in sleep functioning among other opioid dependent populations, including individuals entering methadone maintenance treatment (Dyer & White, 1997; Puigdollers et al, 2004; Sharkey et al, 2011; Wang et al, 2005), treatment seeking heroin dependent individuals (Burke et al, 2008), and recipients of long-term opioid agonist therapy (Stein et al, 2004; Peles et al, 2006). The importance of continued investigation of the effects of PO dependence on sleep are underscored by data suggesting that the effects of opioids on sleep may be greater than that of other substances of abuse (Casola et al, 2006), and that sleep architecture is negatively affected during each stage of opioid dependence: induction, maintenance, acute abstinence, and protracted abstinence (for review see Wang and Teichtahl, 2007).…”