Screen use before sleep and emotional problems among adolescents: Preliminary evidence of mediating effect of chronotype and social jetlag.

BACKGROUND: Screen use before sleep is shown to be positively related to emotional problems. However, whether this relationship was mediated by circadian phenotypes (i.e., chronotype and social jetlag) remains unclear. METHODS: Data from two independent adolescent surveys among 2685 and 1368 adolescents, respectively, were used. Adolescents reported screen use before sleep (yes/no and screen time), chronotype, social jetlag, and emotional problems using questionnaires. Serial mediation analyses were performed. RESULTS: Adolescents who reported screen use before sleep showed later chronotype and greater social jetlag, which was further associated with a higher level of emotional problems. Such relationships held for screen use as a yes/no variable and screen time. The serial indirect effect of chronotype and social jetlag accounted for 6.2%-16.7% of the total effect of screen use before sleep on emotional problems. LIMITATIONS: The use of a cross-sectional design did not allow the establishment of causal links between the variables. All data were self-reported by adolescents, and might be subject to report bias and recall bias. CONCLUSIONS: These findings contributed to the existing literature by examining the mediating effect of chronotype and social jetlag in the relationship between screen use before sleep and emotional problems from a circadian rhythm perspective. Healthy media use habits and interventions targeting circadian characteristics may work towards promoting emotional health in adolescents.