I wonder if their attachment issues is what causes this phenomenon of a “favorite person”. I heard that childhood neglect and abuse can contribute to this diagnosis. I’m also aware that men can have it too but I read that around 75% of diagnoses are women. I’m not sure on the prevalence of BPD but it seems decently high especially if the severity truly is near schizophrenia level like you said.
There’s at least two different theories that I know of ie one is it’s simply genetic meaning the girl will develop it regardless of how her parents raised her but the most popular and prevalent theory is it has to do with severe neglect usually from their mother as an infant.
Thus with every relationship they have the guy or FP is merely a hollow cardboard cut out stand in for mommy but neither he nor she is consciously aware of that.
The BPD never sees you (who you are) and doesn’t love you (they lack the ability since they never formed a true self and true identity in childhood due to the parental neglect so they exist only through facades of mirroring other’s personalities ie what the other person wants to see reflected back at them).
Which is why most people falsely come to believe that the BPD is their soulmate or their best friend ever etc but they find out that’s not true soon enough because the BPD never being able to bond and attach to them eventually discards them for a new FP savior figure to begin the failed from the start process all over again to attempt a do over with their mother through the new partner to finally get her mother to love her.
Which never ever works because the new partner just like you are not her mother and she’s a grown adult now and that ship has sailed.
Most of them even when made aware of this and what’s going on with their relationships will just put their fingers in their ears and stay sick since it’s easier.
Those that do the work to heal with a professional can obtain real stability and stop hurting themselves and others after about two years of hard work but they still shouldn’t date or attempt close friendships until their therapist says they are ready.
And some find out that the best thing for their continued mental health is to never date again.
The damage that happens to some of them from the disconnect with their mom as an infant I believe can permanently wreck their ability to ever be able to tolerate intimacy safely.
Intimacy is what they absolutely cannot handle without treatment and it’s intimacy that ultimately causes them to psychologically split on people and devalue and discard them.