Forms of non-suicidal self-injury as a function of trait aggression.

To date, the considerable body of research on predictors of non-suicidal self-injury (NSSI) has conceptualized NSSI as a unitary construct despite the fact that NSSI can exist in many forms (e.g., hitting, cutting, burning). The goal of the present study is to examine differential prediction of forms of NSSI. Specifically, we examined trait aggression as a predictor of more aggressive forms of NSSI (i.e., hitting). We hypothesized that higher trait aggression would differentiate those who engaged in hitting forms of NSSI from those who did not, whereas other factors (i.e., emotion regulation and trait anger) would serve as a non-specific predictor of NSSI. We also hypothesized that higher trait aggression would be related to lifetime frequency of hitting NSSI, but not other forms of NSSI, whereas emotion regulation and anger would act as predictors of other forms of NSSI. To test these hypotheses, a large sample of young adults completed measures of trait aggression, trait anger, emotion regulation, and NSSI behaviors. Results were generally in line with our hypotheses. Higher levels of trait aggression differentiated those who engaged in hitting NSSI from those who did not and was also associated with greater frequency of hitting NSSI. These results imply that different factors predict different forms of NSSI and that NSSI may be best examined as a multi-faceted construct.