One thing I don't see is patients with borderline personality disorder get better spontaneously. It doesn't happen.
I've seen borderlines get better without professional therapy, but these people had things in their life that highly emulated therapy such as a desire to get better, a positive and close relationship with someone with extreme patience, etc. It's rare. I've also seen several symptoms dampen in intensity, though I don't think it's because the disorder necessarily got better. It's more likely, IMHO, that the person was just getting older, and some things that lead to the impulsivity criteria, such as a strong sex drive, just happen to weaken.
I know a psychiatrist with borderline PD. She never had it to the point of hospitalization, nor did she do any of the parasuicidal behaviors. Her homelife was excessive chaotic, in fact on one occasion, one of her kids called the police on her because she was verbally abusing him excessively, then slapped him. The police officer took it to just be "discipline." In any case, no one at her job knew about it because at work, she put on a good face, but at home, she was borderline to the point of dysfunctional family, GAF of low 60s.
At the wedding of her daughter, I saw an episode where she was screaming at her daughter during a photoshoot, claiming something to the effect of the daughter was "jealous" of her and that the wedding was a nightmare (which by the way was beautiful except for the above) and it must've been the daughter's "revenge" for the years of torment the mother gave her. The daughter was in tears.
But like I said, this psychiatrist, when she showed up to work, never showed any traits. I guess she had enough insight to know to keep that aspect of herself quiet in that setting.
She had the following criteria
A pattern of unstable and intense interpersonal relationships characterized by alternating between extremes of idealization and devaluation.
Identity disturbance: markedly and persistently unstable self-image or sense of self.
Affective instability due to a marked reactivity of mood (e.g., intense episodic dysphoria, irritability or anxiety usually lasting a few hours and only rarely more than a few days).
Chronic feelings of emptiness
Inappropriate anger or difficulty controlling anger (e.g., frequent displays of temper, constant anger, recurrent physical fights).
Transient, stress-related paranoid ideation, delusions or severe dissociative symptoms
I knew about this person because they lived next-door to me while growing up. I was close with their kids, and I knew what was going on behind closed doors. I did some work at the hospital she worked at.
The disorder comes in various degrees. We psychiatrists often see the worst parts of the spectrum. Lots of people have it, but to a degree where they don't have to be hospitalized, and can function in society, though with problems.
This person I mentioned, also worked in a setting where psychiatric patients were often medicated, the patients had a severe mental disorder (e.g. psychosis to a bad extreme) and psychotherapy wasn't often utilized. I speculate that her own lack of psychotherapy knowledge did not give her nudge to introspect herself and her own issues.
Point being that someone with a high level of education and achievement can still suffer from a personality disorder.