Is comorbidity of posttraumatic stress disorder and borderline personality disorder related to greater pathology and impairment?

OBJECTIVE: The authors examined whether patients with comorbid borderline personality disorder and posttraumatic stress disorder (PTSD) have a more severe clinical profile than patients with either disorder without the other.

METHOD: Outpatients with borderline personality disorder without PTSD (N=101), PTSD without borderline personality disorder (N=121), comorbid borderline personality disorder and PTSD (N=48), and major depression without PTSD or borderline personality disorder (N=469) were assessed with structured interviews for psychiatric disorders and for degree of impairment.

RESULTS: Outpatients with diagnoses of comorbid borderline personality disorder and PTSD were not significantly different from outpatients with borderline personality disorder without PTSD, PTSD without borderline personality disorder, or major depression without PTSD or borderline personality disorder in severity of PTSD-related symptoms, borderline-related traits, or impairment.

CONCLUSIONS: The additional diagnosis of PTSD or borderline personality disorder does little to augment the pathology or dysfunction of patients who have either disorder without the other.