When thinking impairs sleep: trait, daytime and nighttime repetitive thinking in insomnia

Abstract

Background: Insomnia affects physical and mental health adversely, but evidence-based interventions are not effective for all insomnia patients. Identifying malleable determinants of insomnia is therefore important. Repetitive thinking (worry, rumination) may be a such a determinant, but research found inconsistent relationships between trait repetitive thinking and sleep diary measures. To explain these results, we investigated effects of timing and thematic content of repetitive thinking in people with insomnia. Methods: In Study 1, 139 participants completed baseline questionnaires on trait worry and rumination, anxiety, depression, insomnia and a sleep diary. In Study 2, 64 participants completed similar measures and a daytime and nighttime sleep-related worry diary. Multilevel models with baseline measures as between subjects variables and (Study 2) daytime and nighttime worry as within-subject variables, were run. Findings: In Study 1, trait rumination and worry were not associated with sleep problems. In Study 2, only nighttime sleep-related worry was consistently associated with sleep impairment . Discussion: Nighttime sleep-related worry may maintain insomnia, while trait and daytime repetitive thinking have benign effects. Insomnia treatment may be improved by specifically targeting nighttime sleep-related worry.