Testing a Theoretically-informed Diathesis-stress Model of Non-suicidal Self-injury

Introduction: The purpose of this study was to investigate the relationship between interpersonal stress and non-suicidal self-injury. Although several theoretical diathesis-stress models of NSSI have proposed potential explanatory variables contributing to the pathway between both distal and proximal interpersonal stress experiences and NSSI, no prior research has sought to empirically validate these pathways in a single sample of adult community participants. The current study focused on exploring the roles of specific emotional and cognitive vulnerabilities that may contribute to why and how interpersonal stress and NSSI are associated. Methods: This study consisted of two phases, a baseline phase and a two-week daily diary phase. Participants were recruited online using social media and community mental health boards. Baseline participants included 202 community adults with and without histories of NSSI. They completed measures of childhood trauma, and emotional and cognitive vulnerabilities. Participants with recent NSSI were eligible to participate in the daily diary phase of the study. Daily diary participants included 59 community adults who completed nightly diaries for two weeks about their daily experiences with interpersonal stress and NSSI. Results: In order to examine the influence of distal interpersonal stress on NSSI, mediation models were tested using emotional and cognitive diatheses as serial mediators. Results indicate that difficulties with emotion dysregulation partially explain the association between the distal interpersonal stress of cumulative childhood trauma and adult NSSI. However, contrary to predictions, cognitive vulnerabilities did not appear to contribute to this pathway. In examining daily relationships, proximal interpersonal stress predicted same-day, but not next-day, NSSI thoughts and urges. This relationship was moderated by trait dysfunctional attitudes, but not emotion dysregulation or rumination. Reports of interpersonal stress did not independently predict same-day or next-day NSSI thoughts/urges or behaviors. Conclusion: This study is one of first to investigate various aspects of a theoretically-derived diathesis-stress model of NSSI in an online sample of community adults, and thus represents an important contribution to the generalizability of prior research in this area. This study is also the first to examine the role of trait diatheses in the temporal relationships amongst daily interpersonal stress and NSSI