It is unclear whether Axis II psychopathology or co-morbid clinical syndromes result in the treatment-seeking behaviour and social impairment of patients with borderline personality disorder (BPD). This study examined the independent associations between social functioning and service use and Axis I and Axis II disorders in persons with BPD in the national household population of Britain.

The study was a cross-sectional survey of adults aged 16–74 years in households (n=8397). Data included self-reported consultations with health-care professionals and behavioural problems. Diagnosis was determined by computer-assisted interviews. Analyses included logistic regression adjusting for demography, co-morbid Axis I clinical syndromes and other Axis II disorders.

Consultation in the past year was reported by 57.5% of persons with BPD but only 13.4% reported lifetime psychiatric admission. BPD was not independently associated with impaired functioning but was associated with co-morbid psychotic, depressive and anxiety disorders. Only general practitioners (GPs) were consulted for problems independently due to BPD.

Functional effects of BPD are mediated through co-morbid clinical syndromes, not Axis II psychopathology. A subgroup do not have co-morbid disorders or seek treatment, and are high functioning.