I seriously doubt that it is possible to do a chemical or neurological test on one of these people and find anything but an imbalance. I am aware of several undiagnosed people who have over the years outgrown the symptoms and behavior. It stands to reason that life-side experience will eventually dispel childish concepts and close the gap. It also stands to reason that the greater the gap, or lack of its awareness, the longer it will take. The tragedy is that BPD people usually ruin their lives and many around them before they grow out of it.
Love is a general, pervasive and necessary psychological requirement.
If fear, repression or some other psychic mechanism interrupts the nurturing realized by love, the result is a general breakdown or failure, a cessation of emotional growth and maturation. When the subconscious psyche is accessed for behavioral reference and the feelings necessary for relationships, it brings up the latest version. Permission granted by author who wishes to remain anonymous.