Emotional and behavioral variability are unifying characteristics of borderline personality disorder (BPD). Ambulatory assessment (AA) has been used to quantify this variability in terms of the categorical BPD diagnosis, but evidence suggests that BPD instead reflects general personality pathology. This study aimed to clarify the conceptualization of BPD by mapping indices of variability in affect, interpersonal behavior, and perceptions of others onto general and specific dimensions of personality pathology. A sample of participants who met diagnostic criteria for BPD (n = 129) and healthy controls (n = 47) reported on their daily interactions during a 21-day AA protocol. Multilevel SEM was used to examine associations between shared and specific variance in maladaptive traits with dynamic patterns of functioning. The authors found that variability is an indicator of shared trait variance and Negative Affectivity, not any other specific traits, reinforcing the idea that BPD is best understood as general personality pathology.
Keywords: ambulatory assessment; borderline personality disorder; classification; interpersonal functioning; transdiagnostic.