frequent interruptions have been well studied as environmental
problems contributing to sleep–wake disturbances
for hospitalized patients (BaHammam 2006). In contrast,
patient mood has been understudied in hospitalized
patients, even though researchers have shown that
depressed mood is highly associated with sleep disturbances
and pain in populations across the world (Tang et al. 2008,
Stepanski et al. 2009, Villemure & Bushnell 2009). And
although adequate pain management continues to be an
global issue for hospitalized adults (O’Malley 2005, Sawyer
et al. 2010), pain in adult medical inpatients has not been
given as much research attention compared with the pain
of post-surgical, cancer, or chronic pain patients (Helfand
& Freeman 2009).