A personality disorder characterized by impulsive behavior and unpredictable, capricious mood. Affected individuals show a tendency to have outbursts of emotion and an inability to control these behavioral explosions. They generally experience an intense fear of abandonment or instability and also struggle with feelings of emptiness. The phenotype is Human Phenotype Ontology entry HP_0012076 (Borderline personality disorder). Also known as: BPD, EUPD, Emotionally unstable personality disorder.