To Örebro University

Background: Previous reports have highlighted the abundance of cognitive constructs in insomnia research as a growing issue. Several questionnaires that measure sleep-related cognitions have been developed and there are indications of conceptual overlap between different cognitive constructs and the questions used to operationalize them.

Objectives: This study examines the convergent validity of three established questionnaires measuring cognitive processes in insomnia: the Anxiety and Preoccupation about Sleep Questionnaire (APSQ), the Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS-10), and the Pre-Sleep Arousal Scale (PSAS-C). Another objective was to explore how a briefer scale can be structured as well as to investigate this scale's ability to predict incident and persistent insomnia compared to the established scales.

Methods: 2333 participants from the general population completed surveys on insomnia symptoms and cognitive processes at baseline and 18 months later. Confirmatory factor analysis was used to investigate the scales' conceptual overlap as well as distinctive factors. An exploratory factor analysis was conducted to investigate the underlying factor structure of the items from the APSQ, the DBAS-10 and the PSAS-C. This analysis formed the basis of the creation of a new short scale: Sleep Worry 7. Binary logistic regressions were used to assess all scales' abilities to predict incident and persistent insomnia.

Results and conclusions: The overlap between the three scales was neither large enough to conclude that they are measuring the same construct, nor could it be confirmed that they measure three distinct questionnaire-specific cognitive processes within insomnia. The brief scale created within this study was able to predict persistent insomnia at similar levels to the three established scales combined, indicating that it captures important cognitions involved in the maintenance of insomnia. Measuring sleep-related cognitions with fewer items might be beneficial in both clinical contexts and research.