Childhood maltreatment and its dose-response relation with non-suicidal self-injury among adolescents: The mediating role of mobile phone addiction.

Objectives: The associations between childhood maltreatment (CM) and mobile phone addiction (MPA), as well as non-suicidal self-injury (NSSI) have been extensively explored. However, the dose-response relationship between CM and NSSI remains inconsistent. Furthermore, there is limited understanding of the potential mediation effect of MPA on the relationship between CM and NSSI. This study aimed to explore the dose-response relationship between CM and NSSI and investigate the potential mediating role of MPA in this relationship.

Study design: Cross-sectional study. Cross-sectional study.

Methods: In the cross-sectional study, a total of 21481 adolescents were selected using a multi-stage cluster sampling method in China. CM, MPA, and NSSI were obtained via self-reports. Data were analyzed using logistic regression models, restricted cubic spline (RCS) functions, and mediation models.

Results: A total of 38.1 % of adolescents reported engaging in NSSI at least once. Compared with participants without CM, participants with more types of CM (cumulative childhood maltreatment, CCM) had a higher risk of NSSI (P-trend in all models <0.001). RCS further confirmed the dose-response relationships between the continuous change in CM (scores) and the risk of NSSI (P for non-linearity <0.001). Mediation analysis indicated that the relationship between CM (scores) and NSSI was mediated by MPA, and the indirect effect (β = 1.07 × 10^-3, 95 % CI: 9.62 × 10^-4, 1.19 × 10^-3) accounted for 22.23 % of the total effect.

Conclusions: There was a dose-response relationship between CM and the NSSI, and the relationship was mediated by MPA. Interventions targeting MPA may reduce the risk of NSSI among adolescents who have experienced CM, particularly those with CCM.