Child abuse: How does it cause borderline personality disorder?

Although traumatic events in childhood are associated with a greater risk of borderline and other personality disorders, the actual cause of personality disorder isn't known. Most likely, no single factor explains its development. Instead it may be caused by a combination of heredity and environmental factors.

Borderline personality disorder is a serious emotional disturbance that's characterized by disappointing and unstable personal relationships, intense anger, impulsive actions, feelings of emptiness, and fears of abandonment — real or imagined. It may be that emotional trauma at a time when the brain isn't fully developed alters something in the brain, which decreases the ability to effectively deal with stressful situations.

Childhood abuse can also be associated with other mental illnesses including depression, post-traumatic stress disorder, anxiety disorders and substance abuse disorders.