The structure of borderline personality disorder symptoms: A multi-method, multi-sample examination

We examined the factor structure of borderline personality disorder (BPD) symptoms by using a multimethod, multisample approach. The factorial structure of BPD has previously been examined through the lens of broad retrospective reports of symptoms without directly contrasting results from different samples of participants, with studies producing inconsistent patterns of results. We go beyond previous work by examining symptoms from multiple timeframes and by examining results across and within 2 diagnostic groups - individuals with and without BPD. Participants (n = 281) completed a structured clinical interview for personality disorders, 2 weekly reports of BPD symptoms, and 2 weeks of in-the-moment "immediate" symptom reports, assessed 5 times daily. Across all participants, results revealed a robust 1-factor structure that replicated across all assessment methods. Moreover, these results replicated within each diagnostic group, with the lone exception of an unclear structure in interview assessment among participants who had a BPD diagnosis. Results have implications regarding the nature, assessment, and treatment of BPD.