Evaluation of a Dimensional Adaptation of Good Psychiatric Management (GPM-extended) for the Treatment of Borderline Personality Disorder

The goal of this clinical trial is to evaluate whether a dimensional adaptation of Good Psychiatric Management (called GPM-extended) is more effective than classic Good Psychiatric Management (GPM) in treating adult patients with borderline personality disorder (BPD). Briefly, the GPM-extended model integrates elements from existing adaptations of GPM for narcissistic and obsessive-compulsive personality disorders. It aims to provide a more personalized and dimensional approach to treatment, tailored to each patient's specific personality dysfunction and interpersonal triggers. The main questions it aims to answer are: * Does GPM-extended improve overall BPD symptom severity more than classic GPM after one year of treatment? * Does GPM-extended lead to better outcomes in related clinical domains (e.g., personality functioning, emotional regulation, social functioning...) ? Researchers will compare two groups: * Patients treated in a center using the GPM-extended program. * Patients treated in a center using the classic GPM program. In each group, patients will receive weekly outpatient psychiatric care for one year. In terms of evaluation, patients will be evaluated at baseline, 4 months, 8 months, and 1 year. They will undergo both clinician-administered and self-report assessments to measure BPD symptoms and other relevant psychological dimensions. This study hopes to contribute to the development of dimensional evidence-based treatments for personality disorders.