a situation wherea person experiences a repetitive pattern of disorganization and instability in self-image, mood, behavior and close personal relationships. This can cause significant distress or impairment in friendships and work. A person with this disorder can often be bright and intelligent, and appear warm, friendly and competent. They sometimes can maintain this appearance for a number of years until their defense structure crumbles, usually around a stressful situation like the breakup of a romantic relationship or the death of a parent.