A psychometric investigation into two insomnia-specific measures of worry/rumination: the pre-sleep arousal scale and the anxiety and preoccupation about sleep questionnaire

Introduction: The aim with this investigation was to psychometrically evaluate two insomnia-specific measures of worry/rumination: the Pre-Sleep Arousal Scale (PSAS; cognitive subscale) and the Anxiety and Preoccupation about Sleep Questionnaire (APSQ).Methods: From a randomly selected sample from the general population (N = 5,000), 2,333 participants filled out a survey on sleep, daytime impairment, PSAS-C, and APSQ.Results: Exploratory factor analyses showed that for both PSAS-C and APSQ only one factor was retained (total variance: 64% and 69%). One of the PSAS-C items fitted less well in the solution (‘being distracted by sounds, noise in the environment’). The internal consistency for PSAS-C was .92 and for APSQ .95, and the two measures were highly correlated (r: .67). Both measures were correlated with sleep onset latency (r: .43-.50), wake time after sleep onset during night (r: .44-.46) and morning (r: .31-.34), sleep quality (r: .55-.60), and with sleep restoration (r: .51-.54). The two measures were correlated with daytime symptoms and function (r: .27-.57). On both measures, significant mean differences were noted between three groups with differing insomnia symptomatology; insomnia disorder group reported significantly higher scores than insomnia symptoms and normal sleep groups, and insomnia symptoms group had significantly higher levels than normal sleep group.Conclusions: In all, PSAS-C and APSQ are both psychometrically sound measures for assessing worry/rumination in insomnia.