Delaying Bedtime Bridges High Social Media Use and Poor Sleep Health in Adults: A Multilevel SEM Analysis

Multiple cross-sectional studies have found an association between high social media use and poor sleep health outcomes in adult populations. However, there are limited longitudinal studies that have explored these associations at the within- and between-person level using objective measures, which restricts causal inferences. The present study aimed to investigate the daily and stable association between social media engagement and both sleep duration and sleep quality in adults, with a specific focus on evaluating the potential mediating role of bedtime. A sample of 119 adult participants (M _age = 26.84) were assessed for a 15-day period, and they provided data for 7 days during this timeframe using two Android applications measuring (a) social media use, (b) bedtime, and (c) sleep duration. Participants also reported on their subjective sleep quality each morning. Multilevel analyses revealed that spending more time on social media at both the within-person and between-person level delayed bedtime, which in turn reduced nightly sleep duration and resulted in poor self-reported sleep quality the following morning. These results highlight that future interventions should target sleep scheduling strategies, not solely social media reduction, to facilitate improvements in adults' sleep health. Clinical trial number: not applicable