Risk and Protective Pathways of Non-Suicidal Self-Injury

Investigations of non-suicidal Self-Injury (NSSI) have centred on constitutional risk factors, such as symptoms of mental illness. Studies investigating risk and protective factors have favoured measures of internal attributes in terms of depression, anxiety, impulsivity, and trait resilience. However, there are a relative paucity of studies and theoretical models highlighting structural risk factors (i.e., social-economic variables), and importantly, structural protective factors for NSSI engagement. Given NSSI is a prevalent behaviour affecting between 4-23% of adults, and up to 38.9% of university students, investigation of social determinants may inform intervention targets or clarify the role of different factors influencing NSSI engagement. The present thesis aims to investigate structural risk and protective factors and pathways. Study 1 assessed whether a general assay of environmental adversity (EA) predicted NSSI engagement and found the link between EA and NSSI engagement was uniquely mediated by depression, but not by anxiety or impulsivity. This supports the role of broad structural determinants of risk. Study 2 tested whether this mediational pathway was reduced by structural protective factors in childhood, such as access to green space, school engagement, and access to supportive adults. Group level differences were observed for some structural protective factors including access to family adults, organised leisure activities, and childhood socioeconomic status. However, structural advantages did not confer protection in the risk model. Given that past structural advantages did not appear to be protective, but general endorsement of EA and greater depressive symptoms conferred risk, study 3 tested whether the ability to prospect future goals was reduced. Past literature has identified differences in future goal prospection are associated with trauma exposure, high depressive symptoms, and outcomes such as suicidal ideation. However, the role of future goal prospection in NSSI is unclear. We found that, for individuals reporting past year NSSI engagement, the representation of future goals was significantly less future-focused, based on text frequency analysis, compared to controls who had not engaged in NSSI. Thus, prospective ability for future advantages may be an important protective factor, compared to past structural advantages for individuals engaging in NSSI.