Exploring the relationship between posttraumatic stress disorder and deliberate self-harm: the moderating roles of borderline and avoidant personality disorders.

Despite increasing evidence for an association between posttraumatic stress disorder (PTSD) and deliberate self-harm (DSH), few studies have examined the factors that moderate this association or the impact of co-occurring personality disorders among individuals with PTSD on DSH frequency. Given the high rates of co-occurrence between PTSD and two personality disorders of particular relevance to DSH, borderline personality disorder (BPD) and avoidant personality disorder (AVPD), this study examined the moderating role of these personality disorders in the association between PTSD and DSH frequency among a sample of substance use disorder patients (N=61). Patients completed structured clinical interviews assessing PTSD, BPD, and AVPD and a questionnaire assessing DSH. Results revealed more frequent DSH among patients with (vs. without) PTSD and provided evidence for the moderating role of AVPD in this association. Specifically, results revealed heightened levels of DSH only among PTSD patients with co-occurring AVPD. Findings are consistent with past research demonstrating that the presence of co-occurring AVPD among patients with other Axis I and II disorders is associated with worse outcomes, and highlight the importance of continuing to examine the moderating role of AVPD in the association between PTSD and a variety of health-risk behaviors.