Chen, ChengChengChenDr. ZHANG Xiao, GraceGraceDr. ZHANG XiaoDr. LEUNG Ka Kuen, DennisDennisDr. LEUNG Ka Kuen2025-09-162025-09-162025Telematics and Informatics, 2025, vol. 102, article no. 102323.0736-58531879-324Xhttp://hdl.handle.net/20.500.11861/25367Fear of missing out (FoMO) has consistently been associated with problematic social media use in cross-sectional survey studies. Given that problematic social media use is not formed overnight, it remains unclear whether FoMO influences the development and escalation of problematic social media use over time. In addition, as FoMO often drives social media engagement, and certain types of engagement can lead to problematic use, this study examines whether different types of social media engagement—broadcasting, lurking, and connection—mediate the relationship between FoMO and problematic use. Using two-wave panel survey data (N = 447) from Hong Kong, we find that FoMO is positively related to problematic social media use in cross-sectional data, but it does not predict problematic behavior once it is established at Time 1. In addition, both social media broadcasting and connection positively mediate the relationship between FoMO and problematic use, even after controlling for prior levels of problematic use. In contrast, lurking mediates the relationship between FoMO and problematic social media use concurrently but not longitudinally. Theoretical implication for applying the Theory of Uses and Gratifications to understand the relationship between FoMO and unintended media use outcomes and practical implication for preventing FoMO-driven problematic social media use are discussed.enPeer Reviewed Journal Article10.1016/j.tele.2025.102323