The provided text offers a comprehensive overview of Borderline Personality Disorder (BPD), beginning with its definition as a complex mental health condition characterized by pervasive instability in emotions, behaviors, self-image, and relationships. It details the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) criteria, which include features like fear of abandonment, unstable relationships, identity disturbance, and impulsivity. The source further explains the historical evolution of the BPD diagnosis, clarifying its distinction from conditions like bipolar disorder and complex PTSD. Finally, it elaborates on the biosocial and neurobiological underpinnings of BPD, emphasizing the role of both genetic vulnerabilities and invalidating environments, and thoroughly discusses evidence-based treatments such as Dialectical Behavior Therapy (DBT), Mentalization-Based Treatment (MBT), and Transference-Focused Psychotherapy (TFP), alongside self-management strategies and the hopeful prognosis for individuals living with the disorder.