Rhythmicity of sleep and impact of safety behaviors

Primary insomnia is a persistent disorder that is characterized by waxing and waning symptoms (APA, 2002). The DSM-IV TR (APA, 2002) states that individualswith insomnia must complain about the inability to fall asleep, stay asleep, wake too early, or wake unrefreshed for a duration of at least one month. Therefore, there is a certain level of variability that exists innately with this disorder. Only a few studies have empirically studied the variability or rhythmicity of sleep (Vallieres, Ivers, Bastien, Beaulieu-Bonneau, & Morin, 2005; Perlis et al., 2009; Buysse, Cheng, Germain, Moul, Frazen, Fletcher, et al., 2010). Two of the three groups of researchers identified an underlying pattern in the sleep of individuals with insomnia. However, one study (Buysse et al., 2010) concluded that there was a pattern in older adults that were good sleeper but did not find a pattern in those with insomnia. The present study utilized an archival data set of 66 individuals (33 participants with insomnia (PIs) and 33 controls (GSs)). We found that individuals with insomnia were likely to have a relatively good night's sleep within 2-3 days, which replicated the Perlis et al. study (2009). These results were also extended good sleepers. In regards to patterns of sleep, several panel regressions wereused to determine that previous night's sleep did impact the current night's sleep. In addition, time spent in bed on previous nights predicted that an individual would have a decreased SE on the present night. Napping duration did not account for significant variation when accounting for either good or bad sleep. Post hoc analyses revealed that individuals with insomnia had an absolute good night's sleep after 5-6 days of poor sleep; whereas, good sleepers had an absolute good night's sleep within 1-2 days of a poor sleep. To be able to better predict an individual's sleep, one must look at not only the homeostatic drive but to other factors that might be contributing to the nuances of the day-to-day, which include biopsychosocial factors.