Abstract
BACKGROUND: Peer bullying is a prevalent phenomenon among high school students. This study aimed to investigate the factors that influence peer bullying among this population, along with their associations with teacher‒student relationships and NSSI. Additionally, this study seeks to propose effective preventive measures to mitigate these issues. METHODS: A two-stage longitudinal study was conducted to assess the prevalence and dynamics of peer bullying, teacher-student relationships, and non-suicidal self-injury among 1,329 high school students in Yunnan Province. The study encompassed one year, from October 2021 (T1) to October 2022 (T2). A standardized questionnaire was administered at both time points to systematically gather the data. Structural equation modeling using Amos software facilitated cross-lag analyses, while bootstrap methods were employed to test for potential mediating effects in the model. RESULTS: Gender differences were found in peer bullying and non-suicidal self-injury at both T1 and T2, with males scoring higher on bullying and females scoring higher on self-injury (all p < 0.01). Additionally, males reported poorer teacher-student relationships at T2 (p < 0.01). Cross-lagged analyses revealed that T1 non-suicidal self-injury was a negative predictor of T2 teacher-student relationships (β = -0.345, p < 0.01), while T1 teacher-student relationships negatively predicted T2 peer bullying (β = -0.040, p < 0.01) and T2 non-suicidal self-injury (β = -0.015, p < 0.05). A longitudinal mediation effect was found through teacher-student relationships between non-suicidal self-injury and peer bullying, with an indirect effect estimate of 0.014 (95% CI: 0.001 to 0.027). The mediation was full, as the direct effect from T1 non-suicidal self-injury to T2 peer bullying was not significant (β = 0.045, 95% CI: -0.088 to 0.179). CONCLUSIONS: Our study revealed complex longitudinal associations among peer bullying, teacher-student relationships, and non-suicidal self-injury in high school students. The findings indicate that earlier non-suicidal self-injury predicted higher levels of peer bullying over time, while positive teacher-student relationships were found to partially explain this link. The results suggest that teacher-student relationships may serve as a mediator in the prospective association from non-suicidal self-injury to peer bullying, highlighting the potential protective role of positive teacher-student dynamics in reducing bullying behaviors among adolescents with self-injury tendencies.