Pre-Sleep Smartphone Use and Sleep in Young Adults: A Biopsychosocial Systematic Review (2015–2025)

This systematic review examined associations between pre-sleep smartphone use and sleep outcomes in young adults (18–30 years) using a biopsychosocial analytical framework. Electronic databases were searched for quantitative studies published between 2015 and 2025 assessing smartphone exposure occurring within the final 0–120 minutes before attempted sleep, including in-bed use. Primary outcomes included total sleep time, sleep onset latency, wake after sleep onset, sleep efficiency, and global sleep quality.Reporting followed PRISMA 2020 standards. Due to substantial heterogeneity in exposure definitions, outcome measures, and study designs, synthesis was conducted using Synthesis Without Meta-analysis (SWiM). Certainty of evidence was appraised using the GRADE framework, alongside structured evaluation of measurement validity, reliability, and fairness based on the AERA, APA, and NCME Standards for Educational and Psychological Testing.Across included studies, later and more intensive smartphone use was generally associated with shorter sleep duration, prolonged sleep onset latency, and poorer subjective sleep quality, although effect sizes were small and certainty of evidence was predominantly low. Objective sleep measures yielded inconsistent findings. A pre-specified exploratory subgroup examining swipe-based dating application use identified no eligible studies reporting timing-specific sleep outcomes, indicating a current evidence gap.Findings support cautious interpretation and highlight the importance of measurement precision, exposure timing, and contextual moderators in future research. All conclusions are associative and not causal.