Group Separation and Classification of Non-Suicidal Self-Injury in a University Student Population

Non-suicidal self-injury (NSSI) has gained an increasing amount of attention in the research literature since being included as topic for future research in the DSM-5 (APA, 2013). Currently, two models of NSSI exist, and both place a primacy on the role of the behaviour in regulating negative affect (Chapman et al., 2006; Nock, 2009). Past research has shown that there is considerable heterogeneity in the contextual, functional, and psychiatric profiles of people engaging in this behaviour (Klonsky & Olino, 2008). This underlying heterogeneity likely indicates that distinct sub-populations of people engaging in NSSI exist based on these factors. In the current study, university students were placed into three groups based on the last episode of NSSI (e.g., no history, proximal episode or past year, and distal episode or not within past year) and these groups were separated based on responses to variables covering personality, emotionality, emotion regulation, impulsivity, psychopathology, resiliency, mindfulness, and self-compassion. Results revealed that the NSSI-Proximal year group was best separated from the other two groups by a linear discriminant function conceptualized as compassionate self-care. Higher scores on the function were more indicative of participants in both NSSI groupings. However, results from a MANOVA revealed no significant difference between No NSSI and the NSSI-Distal group on the variables. The results from the study provide additional support for the importance of identifying NSSI sub-groups in order to improvement the prevention and treatment of non-suicidal self-injury.