I have a story, it might help, might not...
well, first, just to be clear, technically... Borderline Personality Disorder can only be diagnosed by a psychiatrist. The odds of someone with BPD going to see a psychiatrist are almost zero. But the little online checklists and stuff can really be helpful for people attempting to have some sort of life with these people.
I used to be "best friends" with a girl who is probably fits this dx. There's no doubt in my mind my heavy drinking kept our friendship together, as she loved to go out and dress up and attract attention, so that was our thing. The first time I quit, I think I was quit for 8 months (maybe one or two slips in there) it ended our friendship. Telling her "no" on anything meant nonstop harassment. So when I didn't want to go out with her, I'd receive ten or twenty texts. All very manipulative. That she was worried I was depressed, she thought my quitting drinking was an "overreaction" to a breakup I had just gone through. That I couldn't just stay home and wallow.
^^^She continued to send me these stupid "you can't keep being a hermit come to the bar/club with me" for about a year until I blocked her. Just this alone made me realize she was not a friend.
She would make up fake emergencies. Her husband raped her. She was in the emergency room getting a transfusion. <---She didn't specify of what
She would send me crazy texts complaining about her husband. She thought that because he didn't take the dishes out of the dishwasher right away it caused mold spores.
I could fill a novel with her strange attention getting texts to me.
A man followed her in the park while she was walking her dog. (This was a classic, as she actually texted me from her home and had managed to both photograph and videotape this scary man at the park)
The valet at a restaurant charged her $10, when last time it was $5, should she call the restaurant and complain? Or the valet company?
She also started sent me texts that had an odd tone to them. "Do you know my friend Greg? He was looking through my photos and he said he knows you." Strange stuff that had a very psycho tone to it.
Or sending me 20 photos of herself in 7 or 8 different dresses and asking me which one she should wear tonight.
My drinking/not drinking had nothing to do with her psycho. She was always off kilter. I didn't pay attention to it in the beginning because my judgment was off and I just wanted to go out and have fun. When I pulled away from her, she went into crazy clingy hyper nobody-gets-away-from-me mode. Which was pretty terrifying. And I tried to set boundaries. Those don't even exist in her world. What normal people recognize as boundaries, to her, that's a challenge!