The development of borderline personality disorder: beyond the biosocial model

Introduction: The biosocial model of borderline personality disorder (BPD) underpins dialectical behaviour therapy (DBT). This study sought to examine several untested aspects of the model. These included the significance of invalidating parenting, the importance of the interaction between this parenting style and childhood emotional vulnerability, whether the model is equally applicable to clinical and nonclinical populations, and whether the difficulties in establishing a therapeutic alliance observed in clients with BPD are also associated with the childhood antecedents of the disorder. Method: 291 students (239 females, 52 males; mean age of 20.33 years) and 148 (135 females, 13 males; mean age of 34.10 years) individuals with a history of borderline traits were administered questionnaires assessing their current levels of borderline traits and emotional dysregulation, in addition to retrospective measures of invalidating parenting, other forms of poor parenting, childhood emotional vulnerability, and a measure of the quality of their most significant therapeutic relationship. Results: Some differences emerged regarding the applicability of the model to the clinical and nonclinical samples. In neither sample was the interaction between childhood emotional vulnerability and a history of invalidating parenting critically important in relation to the aetiology of borderline traits. In the clinical sample, difficulties with establishing therapeutic alliances were associated with current borderline traits, but not with the childhood antecedents of the condition. Discussion: The current study failed to support key aspects of the biosocial model. An early intervention approach with individuals presenting with the childhood antecedents of the disorder may be indicated.