The nurse managing personality disorders, particularly BPD, implements DBT-informed nursing interventions, manages team dynamics affected by splitting, conducts safety assessments for self-harm and suicidal behavior, and navigates complex therapeutic relationships. DBT biosocial theory posits that BPD develops from the transaction between biological emotional vulnerability (innate emotional sensitivity, reactivity, and slow return to baseline) and an invalidating environment (caregivers who dismiss, trivialize, or punish emotional experiences). This creates a pattern where the individual never learns effective emotion regulation strategies and oscillates between emotional inhibition and extreme emotional expression. DBT core skills applicable to nursing: Distress tolerance (crisis survival skills: TIPP -- Temperature change, Intense exercise, Paced breathing, Progressive muscle relaxation; ACCEPTS -- Activities, Contributing, Comparisons, Emotions, Pushing away, Thoughts, Sensations), Emotion regulation (identify and label emotions, opposite action, build positive experiences), Interpersonal effectiveness (DEAR MAN -- Describe, Express, Assert, Reinforce, Mindful, Appear confident, Negotiate), and Mindfulness (observe, describe, participate non-judgmentally, one-mindfully, effectively). The nurse uses these skills both for patient coaching and personal emotional regulation when managing challenging patient interactions.