This document provides an overview of personality disorders, including Cluster B personality disorders. It defines personality disorders as rigid and unhealthy patterns of thinking, functioning and behaving that cause problems in relationships, social interactions, and work or school. Cluster B disorders are characterized by dramatic, emotional or unpredictable behaviors and include antisocial, borderline, histrionic and narcissistic personality disorders. Antisocial personality disorder involves disregard for others' rights through behaviors like violating laws, aggression, and lack of remorse.