To Örebro University

Objective: The purpose was to examine the psychometric properties of the Pre-Sleep Arousal Scale.

Methods: From a randomly selected sample of the general population (N = 5000), 2327 participants completed a survey on nighttime symptoms, daytime symptoms, health outcomes, and psychological processes. The study sample consisted of 1890 participants who did not fulfill criteria for a sleep disorder other than insomnia.

Results: Findings indicated that the PSAS did not produce an adequate factorial solution. When three problematic items were removed, the solution, accounting for 48.5% of the variance, improved (PSAS-13). One subscale, cognitive arousal (alpha = .88), consisted of five items (37.1%), and one subscale, somatic arousal (alpha = .72), of eight items (11.4%). The two factors were significantly inter-correlated (rho = .51) and associated with the PSAS-13 (rho = .91, rho = .80). Among those with insomnia, a shortened PSAS (PSAS-14) was established, which consisted of a cognitive and a somatic subscale (48.6% of the variance). The PSAS-13 and the two subscales showed discriminant validity between three sleep groups (normal sleep, poor sleep, and insomnia disorder) (R-2 = .24-.34). The PSAS-13 and the subscales demonstrated convergent validity with measures on sleep-related worry, sleep-related beliefs, anxiety, and depression. The PSAS-13 and the two subscales were significantly correlated with sleep parameters and daytime impairment.

Conclusion: Though acceptable psychometric properties were established for the PSAS, the cognitive sub-scale's focus upon general pre-sleep arousal and the relatively low variance accounted for calls for further work on and a possible re-conceptualization of the PSAS.