Longitudinal Association Among Sleep Problems and Depressive Symptoms: Within-Person Mediated Effect of Thought Suppression.

While abundant evidence supports an association among sleep problems and depressive symptoms, the underlying mechanisms remain relatively limed. In particular, little is known about how thought suppression may contribute to the dynamic interplay between depressive symptoms and sleep problems during late childhood. This longitudinal study investigated the reciprocal relations among sleep problems and depressive symptoms, and the mediating effect of thought suppression, by using a random intercept cross-lagged panel modeling (RI-CLPM). A total of 554 students (M = 10.56 ± 0.84 years at T1; 41.7% girls) participated in a three-wave longitudinal study conducted at approximately six-month intervals. Results revealed that thought suppression mediated the relationship between depressive symptoms and subsequent sleep problems, with higher depressive symptoms impairing thought suppression, which then led to greater sleep problems. No significant gender differences were observed in these pathways. These findings highlight thought suppression as a potential mechanism linking depressive symptoms to subsequent sleep problems in children, offering new insights into the developmental co-occurrence of sleep and emotional difficulties.