Comparison of fit index of each model.

<div><p>The association between problematic social networking sites use and depression is established, yet the directionality remains to be clarified. This longitudinal study investigated the causal dynamics between the two phenomena by administering a questionnaire to 191 college students from a university in Shandong Province, China, across four assessment points with an interlude of four weeks. The study found that the impact of depression on problematic social networking sites use is not consistently sustained throughout the academic semester. Initially, this impact reached significance, but it waned and ceased to be significant during the mid- and late-semester phases. These findings allude to the possibility that depression acts as a significant precursor to problematic social networking sites use. However, the interaction between them appears to be subject to temporal and contextual shifts. Consequently, interventions tackling problematic social networking sites use should progressively pivot from moderating screen time and social media engagement towards enhancing emotional robustness.</p></div>