Indulge in drugs, having substance abuse disorder, being an addict, however you want to call it. It's strange I rarely see discussion on substances, given that most addicts tend to have BPD (not the other way around though).

Substance abuse is a huge part of my BPD. It's unconsciously my main self-harm and sabotage mechanism. I unconsciously test people by being mad drunk and drugged right next to them, then I get rejected because no one likes being next to a fiend. Then comes "I knew it".  Then I start using 24/7 to mellow the mood swings. Then comes attempting to OD only to pussy out and still end up in ER by myself because a stranger found me in the street or similar shit.

I also use big time the 5% of the time that I feel elated. Which leads to external violence and problems with authority.

That's how things are for me, what about you? Never had to physically harm myself, others did it to me while  growing up. And alcohol was always there as a kid.Not proud of addiction, I'd rather be dead thrice.