Learning engagement mediates the association between problematic internet use and social withdrawal among Chinese college students

The ubiquity of digital technology has precipitated a rise in Problematic Internet Use (PIU), posing severe risks to college students’ psychosocial well-being, particularly by inducing social withdrawal. Grounded in the I-PACE model and Self-Determination Theory, this study investigated whether learning engagement mediates the relationship between PIU and social withdrawal, and examined the boundary conditions of this mechanism via demographic moderators. A cross-sectional survey was administered to 2034 Chinese college students. Data were analyzed using Structural Equation Modeling (SEM). Bias-corrected bootstrapping (5,000 resamples) was employed to test mediation, and Multi-Group SEM (MG-SEM) was used to assess structural invariance. PIU demonstrated a robust positive association with social withdrawal (r = .619,p<.001r = 0.619,p<.001) and a significant negative association with learning engagement (r = − .213,p<.001r = − 0.213,p<.001). Mediation analysis confirmed that learning engagement partially mediated the link between PIU and social withdrawal. Crucially, moderation analysis revealed that this structural mechanism is not uniform; it was significantly moderated by gender (Δχ2 = 26.886, p<.001 Δχ2 = 26.886, p<.001) and grade level (Δχ2 = 17.297, p=.008 Δχ2 = 17.297, p=.008). Conversely, the model exhibited structural invariance across residence (Urban/Rural) and binary grouping variables, indicating cross-group stability for these factors. These findings suggest that PIU fosters social withdrawal by depleting students’ learning engagement. The study identifies learning engagement as a pivotal intervention target and underscores the necessity of culturally and demographically tailored strategies—specifically adjusting for gender and academic stage—to alleviate the “digital isolation” of contemporary college students.