The role of circadian preferences in the bidirectional link between sleep quality and depressive symptoms: A cross-lagged panel design.

Abstract

Poor sleep quality is strongly linked to depressive symptoms; however, the mediators of this relationship are not well understood. Circadian preferences (CP) emerge as one of the possible mediators underlying this relationship. Previous studies have focused on clinical samples, employed cross-sectional designs and neglected emerging adulthood stage. This study aimed to explore causal relationships using two-wave longitudinal data. The final sample included 272 students from the University of Zagreb (79% female), aged between 18 and 25 years (M = 20.08, SD = 1.14). The Cross-Lagged Panel Model (CLPM) with mediation was employed to test the bidirectional link between sleep quality and depressive symptoms, considering the mediating effect of CP. According to the results, the relationship between sleep quality and depressive symptoms is reciprocal. The effect size indicates that sleep quality has a statistically significant predictive effect on depressive symptoms over time, and vice versa. Mediation analysis revealed that CP did not significantly mediate the relationship between sleep quality and depressive symptoms. CP significantly influenced sleep quality but did not independently contribute to depressive symptoms, suggesting that other mechanisms may be involved in this relationship, such as genetic influences or emotional regulation. The bidirectional relationship between sleep quality and depressive symptoms has significant implications for effective treatment and the prevention of future issues and poorer prognoses. Environmental interventions designed to enhance sleep quality may prevent the onset of depression or reduce existing depressive symptoms. To maximize the effectiveness of these interventions, further research into the mediators of this relationship is essential.