Assumptions in borderline personality disorder: specificity, stability and relationship with etiological factors.

The specificity and stability of a set of assumptions hypothesized to be characteristic of Borderline Personality Disorder (BPD) was investigated. BPD patients (n = 16) were compared to cluster-C personality disorder patients (n = 12) and to normal controls (n = 15). All subjects were female and diagnosed with SCID-I and -II. Subjects rated a short version of the Personality Disorder Beliefs Questionnaire (PDBQ), with six sets of 20 assumptions each, hypothesized to be characteristic of avoidant, dependent, obsessive-compulsive, paranoid, histrionic and borderline personality disorder. The BPD assumptions (Cronbach alpha = 0.95) proved to be the most specific to BPD patients. Subjects rated the shortened PDBQ again after viewing an emotional video fragment one week later. Despite increased negative emotions, the PDBQ ratings remained relatively stable. Confirming the cognitive hypothesis, regression analyses indicated that the BPD assumptions mediate the relationship between self-reported etiological factors from childhood (sexual abuse and emotional/physical abuse) and BPD pathology assessed with the SCID-II. It is suggested that a set of assumptions is characteristic of BPD, and is relatively stable despite the instability of the behaviour of people diagnosed as having BPD.