Mentalization-Based Therapy for Borderline Personality Disorder: State-Of-The-Science and Future Directions

Introduction

Mentalization-based therapy (MBT) is an evidence-based treatment for borderline personality disorder (BPD) and the second most studied psychotherapeutic intervention for this disorder. Despite its growing prominence, there is a lack of focused reviews summarizing the evidence base from randomized clinical trials (RCTs). This review aims to address this gap and highlight directions for future research.

Methods

This narrative review synthesizes findings from RCTs evaluating MBT for BPD. Building on the seven studies identified in the Cochrane review by Storebø et al. (2020), we conducted an updated search to incorporate RCTs published to 1st April 2025, expanding the evidence base to 14 trials. Eligible studies were assessed for effectiveness outcomes and methodological quality.

Results

While some trials report improvements in BPD symptoms and interpersonal functioning, significant limitations exist. Research has largely focused on symptom reduction, despite concerns about the validity of categorical PD diagnoses. The trials were predominantly conducted in European settings, involving primarily female participants, and did not sufficiently account for BPD severity, comorbidities, or developmental stages. All identified RCTs were at high risk of bias, with significant issues involving attention, attrition, and allegiance bias.

Conclusions

MBT shows promise, but methodological shortcomings and limited generalizability constrain its evidence base. Future research should prioritize rigorously designed trials with diverse samples, assess core personality dysfunction using dimensional models, and explore adaptations for adolescents, older adults, and comorbid mental disorders to improve and broaden the clinical utility of MBT for BPD.