Negative life events and problematic smartphone use among university students: the mediating role of self-efficacy and the moderating role of physical activity

Objectives This study explores how negative life events relate to problematic smartphone use among university students and examines whether self-efficacy acts as a mediator and physical activity as a moderator in this relationship. Methods A cross-sectional survey was conducted among undergraduates at eight universities in Nanchang, China, from November 2024 to March 2025. Validated instruments were used to assess negative life events (ASLEC), self-efficacy (GSES), physical activity (PARS), and problematic smartphone use (SAS-SV). The sample included 2,680 participants (47.6% male, 52.4% female; mean age = 19.60 years). Statistical analyses included Pearson correlation analysis and PROCESS models for mediation and moderation. Results Negative life events were positively correlated with problematic smartphone use and negatively correlated with self-efficacy and physical activity. Self-efficacy partially mediated the relationship between negative life events and problematic smartphone use [indirect effect β = 0.05, 95% CI (0.04, 0.07)], with a significant direct effect. Physical activity attenuated the positive correlation between negative life events and problematic smartphone use (interaction β = −0.01, p < 0.001). Conclusions Negative life events, self-efficacy, physical activity, and problematic smartphone use are interrelated among university students. Enhancing self-efficacy and promoting physical activity may help mitigate problematic smartphone use. However, the cross-sectional design and reliance on self-reports limit causal inference.