What causes personality disorder?

Multifactorial: Frontal, temporal, and parietal lobe abnormalities may be seen possibly due to perinatal injury, encephalitis, trauma, or genetics. May also see diminished monoamine oxidase (MAO) and serotonin levels. The role these play is unknown. Developmental abnormalities secondary to abuse, neglect or incest may be present.

Borderline: There is no easy answer to this. Personality disorders, as well as the human condition in general are shaped by genetic factors in combination with environmental factors. It is characterized by fear of abandonment, impulsivity, self mutilation, extremes of emotion, volatile interpersonal relationships, thinking in all-good or all-bad terms,manipulativeness, &drug/alcohol abuse/depend