An examination of anxiety sensitivity as a moderator of the relation between sleep anticipatory anxiety and sleep onset latency.

Evidence suggests that advancing currently limited knowledge about self-reported sleep onset latency is important for better understanding insomnia. Relatively little research has been conducted to understand factors that affect sleep onset latency. The current study tested a hypothesized role of factors of the global anxiety sensitivity (AS) construct as moderators of the relation between sleep onset latency and physical and cognitive components of sleep anticipatory anxiety. As hypothesized, AS-Physical Concerns moderated the relation between the physical component of sleep anticipatory anxiety and sleep onset latency, even after controlling for age, gender, negative affect, and substance use variables. However, in contrast to prediction, AS-Mental Incapacitation Concerns did not appear to moderate the relation between sleep onset latency and the cognitive component of sleep anticipatory anxiety. These findings are discussed in terms of extant research on sleep onset latency, and future directions for research to advance this body of knowledge are considered. Keywords: sleep onset latency; sleep anticipatory anxiety; anxiety sensitivity ; moderator Latency to sleep onset and problems maintaining sleep are two of the main components of primary insomnia, which affects 30%-35% of adults in the United States (Breslau, Roth, Rosenthal, & Andreski, 1996). Factors related to sleep maintenance have been the focus of several empirical studies (see Benca, 2005 for a review); however, relatively less is known about sleep onset latency. This relatively underdeveloped literature is noteworthy as subjective reports (cf., objective measurement) of sleep onset latency have been linked to primary insomnia. For instance, in a relatively early study in this domain, individuals with insomnia overestimated sleep onset by an average of 36 minutes, in comparison to normal sleepers who overestimated their sleep onset by 0.5 minutes (Moore, Bonnet, & Warm 1981 ). Indeed, overestimation of sleep onset latency is associated with increased rates of primary insomnia (Downey & Bonnet, 1992). This research suggests that examination of factors associated with self-reported sleep onset latency may advance understanding of insomnia and related sleep problems. One factor that has been the subject of empirical attention in terms of sleep onset latency is anxiety. Broadly, anxiety occurring upon entering bed may be associated with self-reported delayed sleep onset, which may further increase presleep anxiety, increasing reported sleep onset latency, and so on. This vicious cycle may ultimately culminate in primary insomnia. In fact, anxious cognitive arousal, such as worry (Borkovec, 1982), and anxiety about obtaining insufficient sleep (Lundh, 1998) have been linked to the maintenance of insomnia (Harvey, 2002). In a related way, physiological arousal at sleep onset has been linked to problems with sleep onset and sleep maintenance (Frankel, Buchbinder, Coursey, & Snyder, 1973; Monroe, 1967). In a series of experiments, Tang and Harvey (2004) manipulated cognitive and physiological arousal and measured the effects on perception of several sleep-related factors, including sleep onset latency and total sleep time. In one experiment, participants were instructed to take a nap in a sleep research laboratory. They also were told that upon waking they would have to either give a speech (anxious cognitive arousal), complete an essay (neutral cognitive arousal), or neither. In a separate experiment, physiological arousal was manipulated via administration of 5 mg/kg of caffeine as compared to a placebo control, prior to instructions to nap. Measures of sleep onset latency and total sleep time were obtained through actigraph measures as well as self-report upon awakening. Participants in both the anxious cognitive and increased physiological arousal groups had greater self-reported sleep onset latency in comparison to the nonmanipulated group. …