Beyond Screen Time: Associations of Smartphone Use and Addiction Severity with Cervical Proprioception and Sleep-Related Outcomes

Abstract

Objective: To examine the independent associations of average daily smartphone usage and smartphone addiction severity with cervical proprioception and sleep-related outcomes in university students. Pearson correlations and hierarchical multiple regression were used, with Benjamini–Hochberg FDR correction for multiple comparisons. Methods: This cross-sectional study included 159 students aged 18-24 years. Smartphone addiction was assessed with the Smartphone Addiction Scale–Short Version, and average daily smartphone usage was obtained from built-in screen-time records. Cervical proprioception was evaluated using laser-measured joint position error (JPE). Sleep quality, insomnia severity, bedtime procrastination, anxiety, and depressive symptoms were assessed using the Pittsburgh Sleep Quality Index, Insomnia Severity Index, Bedtime Procrastination Scale, Generalized Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire-9 (PHQ-9), respectively. Pearson correlations and hierarchical multiple regression were used, with Benjamini–Hochberg FDR correction for multiple comparisons. Results: Mean smartphone usage was 342.21 ± 133.70 min/day. In hierarchical regression models, average daily smartphone usage was independently associated with insomnia severity (β =. 0.39, P < .001), poor sleep quality (β = 0.36, P < .001), and bedtime procrastination (β = 0.28, P = .004). These associations remained significant after additional adjustment for PHQ-9 and GAD-7 scores. Patient Health Questionnaire-9 was independently associated with insomnia severity and sleep quality, whereas GAD-7 was not significant. Smartphone addiction severity was independently associated with flexion JPE (β = 0.31, P = .001). Its association with bedtime procrastination was not significant after adjustment for depressive and anxiety symptoms. Conclusion: Smartphone usage duration was consistently associated with sleep-related disturbances, whereas smartphone addiction severity was independently associated with flexion JPE. Causal or temporal relationships cannot be inferred. Cite this article as: Yasaci Z, Arslan HN, Çapadan G, Tari N, Uzun N. Beyond screen time: associations of smartphone use and addiction severity with cervical proprioception and sleep-related outcomes. Arch Health Sci Res. 2026, 13, 0138, doi: 10.5152/ArcHealthSciRes.2026.26138.