Introduction: Perceived stress (PS) is strongly associated with sleep disturbances (SD) [e.g. 1 Darling CA, Coccia C, Senatore N. Women in midlife: stress, health and life satisfaction. Stress and health. 2012;28(1):31–40.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]]. Despite the growing body of evidence linking these two variables, research examining the non-recursive relationship is lacking. The effect of coping [e.g. 2 Abe Y, Mishima K, Kaneita Y, et al. Stress coping behaviors and sleep hygiene practices in a sample of Japanese adults with insomnia. Sleep and Biological Rhythms. 2011;9(1):35–45. doi:10.1111/j.1479-8425.2010.00483.x[Crossref], [Web of Science ®] , [Google Scholar]] and quality of life (QoL) [e.g. 3 Bolge SC, Doan JF, Kannan H, et al. Association of insomnia with quality of life, work productivity, and activity impairment. Quality of life Research. 2009;18(4):415.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]] in sleep patterns is also well established.
The main objective of this research was to analyze the bidirectional relation between PS and SD with a model that includes coping and QoL as predictors of both variables.
Materials and methods: This cross-sectional study comprised 987 Portuguese adults (M = 40.90, SD = 17.17) with SD (M = 2.10, SD = 0.55) that completed questionnaires about sleep patterns (BaSIQS [4 Allen Gomes A, Ruivo Marques D, Meia-Via AM, et al. Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS): Reliability, initial validity and normative scores in higher education students. Chronobiology international. 2015;32(3):428–440. doi:10.3109/07420528.2014.986681[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]]), perceived stress (Perceived Stress Scale [5 Trigo M, Canudo N, Branco F, et al. Estudo das propriedades psicométricas da Perceived Stress Scale (PSS) na população portuguesa. Psychologica. 2010;53:353–378. doi:10.14195/1647-8606_53_17[Crossref] , [Google Scholar]], coping strategies (BriefCOPE [6 Ribeiro JL, Rodrigues AP. Questões acerca do coping: A propósito do estudo de adaptação do Brief Cope. Psicologia, Saúde & Doenças. 2004;5(1):3–15. [Google Scholar]]) and QoL (WHOQOL-BREF [7 Vaz Serra A, Canavarro MC, Simões M, et al. Estudos psicométricos do instrumento de avaliação da qualidade de vida da Organização Mundial de Saúde (WHOQOL-Bref) para Português de Portugal. Psiquiatria clínica. 2006;27(1):41–49. [Google Scholar]]). The study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki and the protocol was approved by IUEM Scientific Council. All participants signed informed consent.
Results: Canonical Correlation Analysis’ results showed that the first correlation (0.562), dominated by PS, suggested a direct association with SD. The second correlation (0.146), dominated by SD, suggested a reverse association with PS. The results of a Structural Equation Modeling with PS and SD as dependent variables showed excellent model fit (X2/df =0.916, p = .469, GFI =0.992, RMSEA =0.000 [0.000 - 0.042]). Self-Blame, Positive Reframing, Denial, Self-Distraction, Social Relationships and Environment were significant predictors of PS. Denial and Environment significantly predicted SD.
Discussion and conclusions: SD depends on PS, but no evidence of a direct effect of SD on PS was observed. Despite the bidirectional relationship not having been confirmed, this study supports the importance of PS in the management of SD. Also, we conclude that coping strategies are important factors in explaining PS rather than SD and that social relationships and environment are the two domains of quality of life that are predictors of PS. Environment is also a predictor of SD.