Re: Are you down with the BPD?
...some things to be careful of...
In practice, 'personality disorders' are fairly squidgy. (Which is one reason DSM V is moving towards lumping them together.) So, something like 30% of BPDs have co-morbid NPD. It is probably clearer to think of someone as having a personality disorder with traits XYZ.
Also, in my experience (and the experience of a few others), high sensitivity autistic women can exhibit a lot of BPD traits. I suspect (but have no real basis) that a significant fraction of people with BPD diagnosis are at least mildly autistic and vice-versa. Something a lot of people don't realize is that about 30% of people diagnosed with autism are highly sensitive people. So, not like Spock. More like someone with a gag on their mouth, who sees everything in black and white, is out-of-touch with their emotions, has really high anxiety, and tends to meltdown and start hitting things when frustrated.
...eg...my wife was diagnosed BPD, but with extremely low empathy. And she can't multitask, has mild sensory overload, communication issues, and really odd ritualistic behavior as a child. Kind of a neurotic female version of Data from Star Trek. Or, Rudy Simone (Aspie author), who apparently was diagnosed bipolar and institutionalized for a while. Or, the lady from an Asperger's support groups who seriously resembles my wife and is also in DBT. Or Penelope Trunk (see blog.)
The bright side is that the same sort of therapy is recommended for both groups...more or less - so misdiagnosis probably doesn't matter that much. The dark side is that at least some of those people are confused by parts of the BPD diagnosis. (And sitting in group feeling nothing in common with 'those silly emotional women.') My wife, at least, has been making more rapid adjustments since she figured out the Aspie thing - and coping techniques for Aspie women have had noticeable effectiveness on some of our more stubborn issues. I dunno, but I suspect autistic traits might be somewhat common in women with BPD diagnoses - and some of those traits may be more easily addressed when people are aware of them.*
The characteristics I've noticed (relative to very peripheral observation of more 'typical' BPDs)...a strange innocence (Oh....aigh...I just realized that all those men I dated probably wanted to sleep with me.)...extreme unempathetic honesty...atypical female violence (jumping in front of a tractor...threatening policemen...baseball bats)...lengthy monologues...unreasonable fear of people (did I offend him?)...weird conversational patterns.
...I am very far from an expert...but I've found limited support for this guess in the medical literature. (One paper indicating that autism predisposed people to BPD-like traits. I take that with a grain of salt...publication pressure is so fierce nowadays that you can find a paper indicating practically anything.)
*Or, to put it another way, maybe some of our MCs would have been better able to control their temper's if they'd been aware that my wife was having genuine comprehension issues instead of faking misunderstanding to divert the conversation.