The relationships between non-suicidal self-injury, emotion dysregulation, self-esteem, and self-compassion among young adults in Aotearoa New Zealand : a thesis submitted in partial fulfilment of the requirement for the degree of Doctor of Clinical Psychology at Massey University, Auckland, New Zealand

Abstract

Non-Suicidal Self-Injury (NSSI), also commonly referred to as self-harm, has been found to affect a substantial minority of young people around the world; with Aotearoa New Zealand appearing to have particularly high rates of this behaviour. It is associated with poor mental wellbeing, and of particular concern, future suicidality. The research literature to date has identified that emotion dysregulation is a correlate and possible cause of engaging in NSSI. However, it is unlikely that emotion dysregulation is the only potential cause of engaging in NSSI, and it does not explain why people engage in NSSI specifically rather than using other adaptive or maladaptive coping strategies. This research hypothesises that self-esteem and self-compassion may also play a role in why people harm their bodies to cope with distress. A mixed-methods study was completed examining the relationships between emotion dysregulation, self-esteem, self-compassion, and NSSI. A survey of 239 young adults found that self-esteem was consistently negatively related to NSSI engagement, while emotion dysregulation and self-compassion were related to NSSI engagement depending on the analytic method and frequency measure of NSSI used. While providing some support for the hypotheses, the effect sizes were small and the results did not lend strong support to the suggestion that both self-esteem and self-compassion play a significant role in engagement in NSSI. In the qualitative phase, the same constructs of interest and their relationship to NSSI were discussed with nine interview participants. Five themes in total were generated from the qualitative analysis regarding emotion dysregulation, self-esteem, self-compassion, the availability of ways a person has to cope, and their use of their bodies to manage distress. While this research is limited in its ability to make causal claims due to its cross-sectional design, the results collectively suggest that self-esteem is a stronger and more consistent predictor of NSSI than emotion dysregulation or self-compassion; that emotion dysregulation and self-compassion may not be as predictive of engaging in NSSI as the literature to date would suggest when other psychological factors are controlled for; and that emotion dysregulation is not a sufficient explanation of NSSI.