Definition of Borderline personality disorder:

Borderline personality disorder is a condition characterized by impulsive actions, mood instability, and chaotic relationships.

Causes, incidence, and risk factors:

Personality disorders are chronic patterns of behavior that impair relationships and work. The cause of borderline personality disorder (BPD) is unknown. People with BPD are impulsive in areas that have a potential for self-harm, such as drug use, drinking, and other risk-taking behaviors.

Risk factors for BPD include abandonment issues in childhood or adolescence, sexual abuse, disrupted family life, and poor communication within the family. This personality disorder tends to occur more often in women and among hospitalized psychiatric patients.