<b>Effect of Smartphone Addiction on Sleep Quality Among Medical and Non-Medical Students</b>

Background: Problematic smartphone use is increasingly recognized as a behavioral addiction in young adults and has been linked to sleep disruption, yet discipline-specific differences between medical and non-medical students remain underexplored. Objective: To compare smartphone addiction and sleep quality between medical and non-medical university students and to evaluate smartphone addiction as a predictor of sleep quality. Methods: A cross-sectional observational study was conducted from March to September 2025 across multiple universities in Sialkot, Pakistan, enrolling undergraduate students aged 18–25 years (N=378) with equal representation from medical and non-medical programs (n=189 each). Data were collected using a demographic questionnaire, the Smartphone Addiction Scale–Short Version (SAS-SV; range 10–60), and the Sleep Quality Scale (SQS; higher scores indicate poorer sleep). Group differences were assessed using Mann–Whitney U tests with effect sizes, and linear regression evaluated the association between SAS-SV and SQS. Results: Non-medical students reported significantly higher smartphone addiction than medical students (40.11±8.44 vs 28.08±8.65; p<0.001; r=0.58) and poorer sleep quality (32.82±11.74 vs 28.62±10.27; p<0.001; r=0.19). Smartphone addiction significantly predicted poorer sleep quality (B=0.26, 95% CI 0.16–0.36; β=0.26; R²=0.067; F(1,376)=27.21; p<0.001). Conclusion: Higher smartphone addiction was associated with poorer sleep quality among university students, with non-medical students demonstrating a higher-risk profile. Targeted digital well-being and sleep-hygiene interventions may help reduce sleep disturbance in student populations.