Non-suicidal self-injury (NSSI) is a major concern in both clinical and non-clinical populations. It has been approximated that 65-80% of individuals with borderline personality disorder (BPD) engage in some form of NSSI. Despite such high co-morbidity, much still remains unknown about the relationship between NSSI and BPD symptomatology. The goal of the current study was to identify individual BPD symptoms and higher order BPD factors that increase one’s vulnerability of NSSI engagement among a college sample. It was hypothesized that the BPD factor of emotion dysregulation and the BPD symptoms of affect instability and intense anger/aggression would be associated with the presence and frequency of NSSI. Seven hundred twenty four undergraduates (61.2% female) completed self-report measures of BPD symptomology and NSSI history. Regression analyses revealed that among the individual BPD symptoms, past suicidality, impulsivity, chronic emptiness, and identity disturbance were each significantly, positively associated with lifetime history of NSSI, whereas unstable relationships were negatively associated with lifetime history of NSSI. The BPD symptom associated with NSSI frequency was dissociation. Among the BPD factors, emotion dysregulation and disturbed relatedness were both associated with NSSI history, but only disturbed relatedness was associated with NSSI frequency. Findings show partial support for the importance of emotion dysregulation in the relationship between NSSI and BPD symptomatology, but also suggest that the relationship may be more complex and not solely based on emotion dysregulation.

Research suggesting nonsuicidal self-injury (NSSI) may belong in a distinct diagnostic category has led to the inclusion of NSSI disorder in the DSM-5 section for future study. There has been limited research, however, examining the validity of Criterion A (the frequency criterion). The current study aimed to examine the validity of the frequency criterion of NSSI disorder through the use of an exploratory data mining method, structural equation modeling trees, as a way to determine a NSSI frequency that optimally discriminates pathological NSSI from normative behavior among undergraduate students (n = 3,559), 428 who engaged in NSSI in the previous year. The model included psychopathology symptomology found to be comorbid with NSSI and cognitive-affective deficits commonly associated with NSSI. Results demonstrated a first split between individuals with 0 and 1 act of NSSI in the past year, as was expected. Among individuals with 1 or more previous acts, the optimal split was between those with 5 and 6 NSSI acts in the past year. Results from the current study suggest that individuals with 6 acts of NSSI in past year, compared with those with 5 acts or less, may represent a more severe group of self-injurers. These individuals reported higher levels of related psychopathology symptomology and cognitive-affective deficits, in addition to decreased quality of life. Findings have potential implications for the proposed frequency criteria of NSSI disorder and how pathological NSSI is characterized. (PsycINFO Database Record