Mark Ruffalo, acclaimed actor and mental health advocate, discusses the intricacies of borderline personality disorder (BPD). He explores the historical evolution of BPD diagnosis, highlighting key concepts like splitting and identity diffusion. The conversation addresses the impact of childhood trauma on self-concept and relationships, along with effective therapeutic approaches. Ruffalo emphasizes the importance of empathy in treatment and delves into the emotional dynamics between therapists and patients, offering profound insights for understanding this complex condition.