Longitudinal bidirectional relationships between deviant peer affiliation/core self-evaluation and non-suicidal self-injury among Chinese adolescents

The prevalence of non-suicidal self-injury among Chinese adolescents is worsening. Although adolescents’ peer relationships or self-perceptions have been found to be possible predictors of self-injury, the reverse effects of self-injury and their longitudinal dynamics remain unknown. Participants were recruited from several schools in Anhui Province, China (N = 966, Mage at Time 1 = 15.46) and completed follow-up measures at three-time points at 6-month intervals. Results showed that (1) two vicious circle mechanisms were found in the total sample, namely T2 deviant peer affiliation or T2 core self-evaluation mediating T1 and T3 self-injury. (2) Gender subgroups revealed that compared to boys, girls’ deviant peer affiliation stably predicted self-injury, and T2 self-injury mediated T1 deviant peer affiliation and T3 core self-evaluation. These findings suggest that effective interventions for self-evaluation and peer relationships may be a favorable perspective to reduce self-injury in adolescents and facilitate breaking the vicious cycle of self-injury.