Introduction
Social media use (SMU) has emerged as a ubiquitous aspect of daily life among university students, serving as both a resource for social connection and a potential risk factor for psychological maladjustment. Problematic SMU, defined by compulsive engagement and interference with daily functioning, has been linked to heightened depressive symptoms, anxiety, and perceived social isolation (PSI). This study seeks to elucidate the mechanisms underpinning these relationships, with a focus on PSI as a mediating variable.


Purpose
The objectives of this longitudinal investigation were threefold: (1) to examine the associations between problematic SMU, PSI, and emotional difficulties (i.e., depression, anxiety, and social anxiety); (2) to evaluate the mediating role of PSI in the relationship between SMU and emotional difficulties; and (3) to explore the temporal dynamics of these constructs using cross-lagged panel modeling.


Method
A sample of 187 university students participated in the study, completing surveys at three time points over one month. Validated psychometric instruments, including the Social Media Disorder Scale, Short Loneliness Scale, PHQ-8, GAD-7, and SPIN, were employed. Regression and mediation analyses, alongside cross-lagged panel models (CLPM), were conducted to assess associations, mediation effects, and temporal stability.


Results
Problematic SMU was significantly associated with depressive symptoms (β = 0.23, p < .001), anxiety (β = 0.17, p < .001), and social anxiety (β = 0.45, p < .001). PSI partially mediated the relationship between SMU and depressive symptoms (β = 0.02, p = .024). CLPM analyses revealed strong autoregressive effects for all constructs but weak cross-lagged effects.


Conclusions
The findings suggest that problematic SMU exacerbates emotional difficulties, with PSI serving as a partial mediator. Interventions targeting digital literacy, moderation of SMU, and fostering offline connections may ameliorate these psychological risks. This research advances understanding of the complex interplay between SMU, PSI, and emotional well-being in university populations.