Diagnosing, assessing, and treating complex posttraumatic stress disorder (CPTSD) and borderline personality disorder (BPD).

Complex posttraumatic stress disorder (PTSD) has recently been formally classified as a diagnosis in the World Health Organization’s 11th version of the International Classification of Disease. However, borderline personality disorder and PTSD exhibit overlapping symptoms with complex PTSD, creating ambiguity between these diagnoses, which impacts treatment conceptualization and effectiveness. This article offers an accessible and quick reference guide for clinicians on understanding PTSD, complex PTSD, and borderline personality disorder. This resource addresses the similarities and differences between these disorders, offering interview questions and clinical assessments to help with diagnostic differentiation. Additionally, it includes current treatment recommendations, special considerations, and relevant case vignettes for practical application.