The Co-Occurrence of Trauma Related Disorder and Borderline Personality Disorder: AQ Study on a Clinical Sample of Patients Seeking Psychotherapy Treatment

•The CPTSD and PTSD diagnoses represent separate entities to BPD.•An accurate assessment of BPD, CPTSD and PTSD constructs is important to determine which treatment is more tailored to the patient's difficulties.•A co-occurrence of BPD, CPTSD and PTSD diagnoses has not been observed.•The presence of adverse events does not represent a risk factor for BPD diagnosis. The nature of the relationship between borderline personality disorder (borderline PD), post-traumatic stress disorder (PTSD) and complex PTSD remains controversial. In this study we attempted to investigate the association between traumatic events and borderline PD and the co-occurrence of complex PTSD, PTSD and borderline PD. Finally, we tested the association between complex PTSD and PTSD diagnoses and other DSM-5 Section II personality disorders. In a sample of 416 patients, we administered the International Trauma Questionnaire (ITQ) to evaluate the PTSD/complex PTSD diagnoses and the Structured Clinical Interview for DSM-5 Personality Disorders (SCID-5-PD) and the Personality Diagnostic Questionnaire– 4+ (PDQ-4+) to assess borderline PD and other PDs. One hundred-twenty-three participants reported experiencing one or more traumatic events. Our findings show that the presence of adverse events does not represent a risk factor for borderline PD assessed using both SCID-5-PD and PDQ4+. A co-occurrence of borderline PD diagnoses and complex PTSD/PTSD diagnoses has not been observed. We found a significant association only between complex PTSD and schizoid personality disorder assessed using PDQ4+. Our findings suggest relevant clinical implications for the development of effective treatment for complex PTSD, PTSD and borderline PD.