Self-injury is one of the strongest predictors of suicide. Undergraduates have been recognized as one of the populations with the highest incidence of self-injury. A substantial body of literature has documented the important influence of impulsivity on self-injury. However, few studies have focused on the mediating mechanisms underlying this relationship. Based on the stress generation hypothesis and the affect-regulation model of self-injury, this study constructed a chain mediating model to examine whether stressful life events and negative affect mediated the relationship between impulsivity and self-injury among Chinese undergraduates.

A total of 2270 undergraduates (69.8% female, mean age = 19 years) were recruited to participate in this study and completed self-report measures of impulsivity, self-injury, stressful life events and negative affect.

(1) There were significant positive correlations among impulsivity, stressful life events, negative affect and self-injury. (2) After controlling for the effect of gender, impulsivity still had a significant positive effect on self-injury. (3) Undergraduates’ self-injury was affected by impulsivity partly through 3 different pathways: the mediating role of stressful life events, the mediating role of negative affect, and the chain mediating role of both stressful life events and negative affect.

These findings contribute to a more comprehensive understanding of the risk factors for self-injury. Impulsivity, stressful life events, and negative affect might increase the occurrence of self-injury. In addition, the chain mediating effect of stressful life events and negative affect plays an important role in the occurrence of self-injury.