Complex posttraumatic stress disorder and borderline personality disorder: a truly complex relationship or a diagnostic artefact?

Purpose of review: This review examines the relationship between borderline personality disorder (BPD) and complex posttraumatic stress disorder (CPTSD) in light of recent claims that the former might be replaced by the latter. Recent findings: The stigma associated with BPD is not a convincing reason to suggest that CPTSD is more adequate than BPD, despite the fact that there is currently less stigma attached to it. BPD and CPTSD share some core symptoms, such as affective dysregulation and interpersonal difficulties. However, several features, including impulsivity, identity disturbance, and fear of abandonment, are relatively specific for BPD and may distinguish it from CPTSD. While trauma is a major risk factor for both conditions, it is neither necessary nor sufficient for the development of BPD because it can occur in the absence of trauma. In contrast, trauma is indispensable in the development of CPTSD. Research using latent class analysis and structural equation modeling has produced mixed results, with most studies identifying overlapping symptom clusters of BPD and CPTSD and suggesting that the boundaries between the two conditions are not clear. Summary: While there are many similarities between BPD and CPTSD, they can be distinguished clinically, although the boundaries between them are not clear-cut. Current evidence strongly suggests that BPD cannot be reduced to a trauma-related condition and that it would therefore be erroneous to replace it with CPTSD.