What defense mechanism is most characteristic of Borderline Personality Disorder?

• A. Denial
• B. Acting out
• C. Splitting
• D. Projection

Answer: (C)

Splitting is the defense mechanism most characteristic of Borderline Personality Disorder. It involves seeing people and situations in all-or-nothing terms, swinging between idealization and devaluation. This black-and-white thinking helps manage intense, quickly changing emotions and a deep fear of abandonment. When someone feels close and safe, they may idealize them; when hurt or threatened, they can abruptly devalue them. This pattern underlies the instability of relationships, along with the rapid mood shifts and identity turmoil often seen in borderline pathology. Other defenses like denial, projection, or acting out can occur too, but they’re not as central to the typical presentation as splitting, which directly explains the characteristic push-pull dynamics.