Problematic mobile phone use, loneliness, and life satisfaction among college students during the COVID-19 lockdown in Shanghai: a cross-sectional mediation analysis.

Introduction: During Shanghai's COVID-19 lockdown, college students relied heavily on mobile phones for study, communication, and everyday activities, while normal campus routines and face-to-face contact were sharply restricted. Although problematic mobile phone use, loneliness, and life satisfaction have each received considerable research attention, less is known about how they were related under these unusual conditions. This study therefore examined their cross-sectional associations and evaluated whether loneliness statistically accounted for part of the association between problematic mobile phone use and life satisfaction. Methods: We conducted a cross-sectional online survey of 1,311 freshmen and sophomores from seven public undergraduate colleges in Shanghai during the 2022 lockdown. PMPU, loneliness, and life satisfaction were assessed using validated scales. Pearson correlations and covariate-adjusted ordinary least squares mediation analyses were performed, with indirect associations estimated using 5,000 percentile bootstrap resamples. Sensitivity analyses examined alternative model specifications. Results: PMPU was positively correlated with loneliness ( Conclusion: Greater PMPU was associated with lower life satisfaction among college students surveyed during the Shanghai lockdown, with loneliness statistically accounting for part of this association. However, the cross-sectional design and the non-zero indirect association in the alternative-direction model preclude conclusions about temporal ordering or causal mediation.