Objectives: Relatively few studies have explored the inter-relationship between screen time (ST), sleep duration and depressive symptoms. The study herein sought to determine (1) the relationships between ST, sleep duration and depressive symptoms among Chinese adolescents; (2) whether sleep duration mediates the relationships between ST and depressive symptoms.
Methods: 1st grade students (n=1,976) from ten high schools in Guangzhou, China were invited through cluster sampling between January and April 2019. Self-reported ST with electronic devices and Internet, sleep duration, and The Center for Epidemiology Scale for Depression (CES-D) score were collected. Generalized mixed linear models and mediation analyses were conducted.
Results: There were 1,956 self-reported questionnaires received (response rate: 98.99%). Approximately 25% (471/1,929 for Internet use, 399/1,928 for electronic device) of the total sample reported ST >2 hours/day. Approximately 8.9% (169/1,894) reported a CES-D score >28. Longer ST with electronic devices (estimate=0.52, 95%CI: 0.24~0.80), Internet usage (estimate=0.82, 95%CI: 0.53~1.11) were positively associated with depressive symptoms, while less sleep (estimate=-1.85, 95%CI: -2.27~-1.43) was negatively associated with depressive symptoms. There is significant indirect effect of electronic device usage on depressive symptoms through sleep duration (indirect effect=0.08, 95%CI: 0.01~0.15).
Limitations: This study only included school students from Guangzhou. Causal relationship cannot be inferred by this cross-sectional design.
Conclusions: ST and sleep duration were significantly associated with depressive symptoms severity. The indirect effect of sleep duration suggests a possible mechanism of the association between ST and depressive symptoms. Future interventions to manage depressive symptoms should target sleep time and decrease ST among adolescents.
Keywords: Adolescents; Depressive symptoms; Screen time; Sleep duration.
Copyright © 2021. Published by Elsevier B.V.