Mediating effects of self-esteem in the relationship between childhood maltreatment and non-suicidal self-injury among adolescents: The roles of sex and only-child status

Abstract Rationale Although childhood maltreatment is known to be associated with non-suicidal self-injury (NSSI), few studies have investigated the mediating effect of self-esteem on this relationship. Additionally, it is unknown whether the impacts vary by sex or only-child status. Objective We investigated the mediating effects of self-esteem on the relationship between childhood maltreatment and NSSI in adolescents and identified the significance of sex and only child status. Method An adolescent health survey was conducted in 15 schools in China between 2013 and 2014. In total, 9704 students aged 11–19 years completed standard questionnaires to report the details of childhood maltreatment, NSSI, and self-esteem. Results Childhood maltreatment was negatively correlated with self-esteem and positively correlated with the frequency of NSSI. Lower self-esteem was also correlated with higher NSSI frequency. Self-esteem mediated the relationship between childhood maltreatment and NSSI, and the estimated ratio of the total effect of childhood maltreatment that could be explained by mediation through self-esteem was 16.3%. The ratio was higher in boys (28.6%) than in girls (9.9%), and it was higher in only children (31.5%) than in children with siblings (11.0%). Conclusions Childhood maltreatment is positively correlated with the frequency of NSSI and may be mediated by self-esteem. Interventions aimed at reducing NSSI associated with childhood maltreatment may be enhanced by efforts to strengthen self-esteem, especially in boys and only children.