Loneliness and Problematic Social Network Use Among Rural Left-Behind Children: A Three-Wave Moderated Mediation Study of Fear of Missing Out and Self-Control

Background: Problematic social network use (PSNU) has become an increasingly relevant concern for child well-being because it is characterized by excessive, intrusive, and poorly regulated engagement with social networking platforms. Rural left-behind children may be particularly vulnerable due to prolonged parent-child separation and alternative caregiving arrangements can weaken daily emotional support and increase reliance on digitally mediated social interactions. This study examined whether fear of missing out (FoMO) mediates the association between loneliness and PSNU and whether self-control moderates this pathway. Methods: A three-wave questionnaire survey was conducted among 620 rural left-behind children in China, with two-month intervals between consecutive waves. The time-lagged design was adopted to align measurement with the hypothesized sequence linking loneliness, FoMO, and PSNU and to reduce same-occasion response bias. Loneliness and self-control were measured at Time 1, FoMO at Time 2, and PSNU at Time 3. Reliability analysis, confirmatory factor analysis, descriptive statistics, correlation analysis, subgroup descriptive comparisons, and time-lagged moderated mediation analyses were conducted. Gender and age were included as covariates. Results: Loneliness was positively associated with subsequent FoMO and subsequent PSNU. FoMO was positively associated with later PSNU and significantly mediated the time-lagged association between loneliness and PSNU. Self-control negatively predicted PSNU and significantly moderated the FoMO-PSNU association, such that the association was stronger among children with lower levels of self-control. In addition, the conditional indirect association between loneliness and PSNU through FoMO was also stronger at lower levels of self-control. The measurement model showed acceptable fit, and all four constructs demonstrated satisfactory internal consistency. Conclusions: For rural left-behind children, problematic social network use appears to be closely associated with loneliness, FoMO, and self-control. Prevention efforts may be more effective when they integrate emotional support, consistent parent-child communication, school connectedness, digital literacy education, and self-control training, rather than focusing solely on screen-time restriction. Given the time-lagged observational design, the findings should be interpreted as temporally ordered associations and not as evidence of definitive causal effects.