Causes

As with other mental health disorders, the causes of borderline personality disorder aren't fully understood. In addition to environmental factors — such as a history of child abuse or neglect — borderline personality disorder may be linked to:

• Genetics. Some studies of twins and families suggest that personality disorders may be inherited or strongly associated with other mental health disorders among family members.
• Brain abnormalities. Some research has shown changes in certain areas of the brain involved in emotion regulation, impulsivity and aggression. In addition, certain brain chemicals that help regulate mood, such as serotonin, may not function properly.