Non-Suicidal Self-Injury in Post 9/11 Veterans: Examining the Influence of PTSD, MDD, Their Comorbidity and Psychological Inflexibility
Non-suicidal self-injury (NSSI) refers to the destruction of one’s body without intent to die. NSSI may be used a means of managing negative affect brought about by psychopathology (e.g. post-traumatic stress disorder (PTSD), major depressive disorder (MDD)) that may result from traumatic experiences (e.g. childhood trauma, abuse, neglect). PTSD and MDD both involve feelings of worthlessness, guilt, diminished interest, among others which may influence use of NSSI. For veterans who have killed in combat, symptoms of PTSD and depressive symptoms are associated with an increased desire for self-harm (Maguen et al., 2011). Moreover, these disorders often co-occur. A study by Brown et al. (2001) found with 69% of individuals with PTSD also met criteria for MDD, making it important to study NSSI in the context of both conditions. Further, one process that may influence the effect of PTSD-MDD comorbidity on engagement in NSSI is psychological inflexibility (PI), which involves an individual’s inability to overcome psychological reactions to painful events. It is plausible that PI could play a role in the development and maintenance of NSSI. This study is a cross-sectional, secondary data analysis of a longitudinal parent study, Project SERVE: Studies Evaluating Returning Veterans’ Experiences. The sample consisted of (N=545) male and female post-9/11veterans enrolled in a healthcare facility. The study participants were diagnosed with PTSD, MDD, and comorbid PTSD-MDD, and assessed with respect to lifetime engagement in NSSI. It was hypothesized that individuals with PTSD-MDD comorbidity would show higher frequency of NSSI symptoms than those with PTSD only or MDD only; that PI would be associated with NSSI symptoms, and that PI would moderate the relationship between PTSD, MDD, PTSD-MDD comorbidity and NSSI respectively. Chi square tests, hierarchical logistic and linear regressions, as well as moderation analysis were used to examine the relationships between variables. The aim of this study was to examine the relationships between PTSD, MDD, PTSD-MDD comorbidity and NSSI and to understand the role PI may play between psychopathology and engagement in NSSI.