Non-suicidal self-injury with and without borderline personality disorder: differences in self-injury and diagnostic comorbidity.

Although non-suicidal self-injury (NSSI) occurs in people with and without borderline personality disorder (BPD), few studies have compared the clinical characteristics of these two groups. The present study sampled adults with a history of NSSI and compared those with and without BPD on (a) NSSI features, (b) co-occurring psychiatric disorders, and (c) severity of depression, suicidal ideation and emotion dysregulation. Participants (NSSI+BPD, n=46; NSSI Only, n=54) completed semi-structured interviews and self-report measures. Whereas the groups did not differ in age of NSSI onset, the NSSI+BPD group engaged in more frequent, recent and severe NSSI, and reported higher rates of skin carving, head banging, self-punching and self-scratching than the NSSI Only group. Participants with BPD also showed greater diagnostic comorbidity, particularly for anxiety disorders, but did not differ from participants without BPD in rates of mood, substance or psychotic disorders. The NSSI+BPD group reported more severe depressive symptomatology, suicidal ideation and emotion dysregulation than the NSSI Only group. Supplementary analyses on the subset of participants with recent (past year) NSSI revealed similarly medium to large differences between those with and without BPD. Implications for assessment and treatment are discussed.