I think it's difficult or impossible to adopt a "full" personality. I think it's undesirable to (fully) adopt any cluster B personality or any other dysfunctional personality type, if it were possible.

It certainly is very hard to deal with a borderline personality. It is dysfunctional in many ways. But I hope and believe it must be good for something.

Like all/most cluster B personality types, there is some ability to distance/detach oneself from one's emotions. That is useful.

There is also a more controlled expression in reaction to one's emotions, using the strengths of BP in a more controlled fashion so as to prevent escalation. A form of (defusing) co-optation, in some ways. That is useful.

I think some of that behaviour can be learned/internalised later in life.

The alternative may be more of a schizoid personality, which is in some ways worse.

But if you could have a more normal/healthy personality and function better, having, what I like to call, schizomania, schizoaffective disorder BP-type, schizomania being sometimes used and shorter, I'd take it.

I'm rather confused about BPD, which is typical, so I might see it all wrong. But there must be reasons. I hate the confusion. Lack of apparent reasons. It feels so hopeless. It's a love-hate relationship: how typical!



Edit:
It's infuriating: also typical, in a way.

Another edit:
The main similarity is based on where a borderline personality would fit into the psychotic spectrum, where BP-I borders on SZA and SZ.

Being also known as borderline schizophrenic while being rather like BP, BPD might take the same position as SZA. Maybe you could say that all of BP can be considered borderline schizophrenic, but co-morbidity between BPD and BP-I is higher than that of BPD and BP-II. It's therefore not completely unlikely that the most SZ-like forms of BP-I, arguably SZA rather, have some strong connection with BPD.