<![CDATA[Background: Borderline Personality Disorder (BPD) is a complex personality disorder characterized by pervasive instability in emotion regulation, impulse control, self-image, and interpersonal relationships. From Sigmund Freud's psychoanalytic perspective, these manifestations can be understood as the result of unresolved intrapsychic conflicts involving the dynamics of the id, ego, and superego, accompanied by the predominance of immature defense mechanisms. Clinical documentation of BPD analyzed through a psychoanalytic approach within hospital-based mental health services in Indonesia remains limited, whereas most published case reports have focused on Western populations. Purpose: To analyze the behavioral patterns of a patient diagnosed with BPD (F60.31) through the lens of Freudian psychoanalytic theory. Method: A single case study with a descriptive qualitative approach was used. A comprehensive assessment was conducted through autoanamnesis, alloanamnesis, clinical observation, and medical record review across six sessions on June 2026 Results: Findings revealed persistent emotional dysregulation, high impulsivity, intense fear of abandonment, unstable interpersonal patterns, and a history of self-harming behaviors. The clinical picture met the PPDGJ-III diagnostik criteria for Emotionally Unstable Personality Disorder, Borderline Type. Viewed through Freudian psychoanalytic theory, these patterns reflect a dominant id, an underdeveloped ego, a harsh superego shaped by authoritarian parenting, and reliance on immature defense mechanisms such as splitting, denial, and acting out. Conclusion: The case illustrates how unresolved intrapsychic conflict and immature ego defense mechanisms interact to sustain emotional dysregulation and unstable relationship patterns. Prognosis is considered dubia ad bonam, with Dialectical Behavior Therapy (DBT) and Mentalization-Based Therapy (MBT) recommended for future management. Keywords: Behavior Analysis; Borderline Personality Disorder; Psychoanalytic Theory; Self-Harming Behavior.]]>
