Difficulties in Emotion Regulation Mediate the Association Between Peer Attachment and Problematic Use of Smartphone

ABSTRACT Background Problematic use of smartphone (PUS) is increasingly prevalent among adolescents and may be influenced by both peer relationships and emotion‐regulation capacities. This study tested whether difficulties in emotion regulation mediate the association between peer attachment and PUS, and whether these pathways differ by gender, age, and school type. Methods: A cross‐sectional survey recruited 12,099 Chinese adolescents (mean age = 18.93 years, 58% female) through stratified cluster sampling. Participants completed validated measures of PUS, peer attachment, and the Difficulties in Emotion Regulation Scale (DERS). Structural equation modeling (SEM) examined mediation via a latent DERS factor, controlling for demographics. Multi‐group SEM evaluated moderation across gender, age (> 18 vs. ≤ 18), and school (university vs. high school). Results Peer attachment was negatively associated with emotion‐regulation difficulties ( β = −0.296, p < 0.001) and with PUS ( β = −0.144, p < 0.001). Emotion‐regulation difficulties positively predicted PUS ( β = 0.372, p < 0.001). The indirect effect ( β = −0.110, 95% CI [−0.116, −0.104]) confirmed partial mediation. Multi‐group SEM indicated significant moderation (Δ χ 2 = 76.01–93.70, all p < 0.001): the effect of emotion‐regulation difficulties on PUS was stronger among females; the impact of weaker peer attachment on emotion regulation was stronger among younger adolescents; and school type moderated both the path and the direct effect on PUS. Nevertheless, the mediation pathway remained significant in all subgroups. Conclusions Emotion‐regulation difficulties partially explain the link between peer attachment and PUS in adolescents. The strength of these pathways varies by gender, age, and school context, highlighting emotion regulation as a promising intervention target.