Beliefs related to diagnosing borderline personality disorder and complex post‐traumatic stress disorder

OBJECTIVES: There has been speculation that Borderline personality disorder (BPD) and Complex post-traumatic stress disorder (cPTSD) are the same disorder or represent separate disorders on a broader trauma spectrum. BPD and cPTSD share several symptoms but differ in their presentation. Because the two disorders present so similarly, it could be that clinicians have difficulty differentiating them, leading to misdiagnosis. BPD is a commonly stigmatized condition, and stigma can be a source of diagnostic error, contributing to misdiagnosis. This study examined clinicians' diagnostic decision-making and stigma towards BPD and Complex PTSD. METHODS: Participants (n = 426) completed an online survey where they diagnosed a written case vignette and completed measures of their familiarity with each disorder, stigma and symptom importance for their diagnosis. RESULTS: Results indicated that clinicians were significantly less familiar with BPD than with cPTSD; however, only familiarity with cPTSD predicted diagnostic decisions. Higher familiarity with BPD was associated with lower stigma towards BPD, whereas familiarity with cPTSD predicted lower stigma for both disorders. Stigma levels were significantly higher for BPD than for cPTSD, but only stigma towards cPTSD predicted diagnosis. Symptom ranking strongly influenced diagnosis, with clinicians more likely to assign a diagnosis based on symptoms they associated with BPD or cPTSD. BPD stigma influenced rankings of BPD symptoms, whereas cPTSD stigma affected rankings across all symptom categories. CONCLUSION: These findings suggest that familiarity and stigma play crucial roles in shaping diagnostic decisions and highlight the need for improved clinician training to mitigate biases and enhance diagnostic accuracy.