People with borderline personality disorder generally lack "insight," i.e. they are typically unaware that they have BPD; will deny having it; and will get extremely defensive at the suggestion they have it.

One can contrast with, for example, obsessive/compulsive disorder sufferers who usually do have pretty good insight.

So a survey based on self-reporting is not going to be very helpful.

Anyway, I doubt that there are many people on this board with BPD. This is based on my interactions and observations.

Also, this discussion board doesn't seem like it would be very attractive to someone with BPD since it doesn't offer a steady stream of validation. For example, it's common on this board for other posters, even those who agree with you on a lot of stuff, to challenge, question, or downvote your posts. For someone with BPD, that would be pretty difficult to handle.

The main mental issue I sense on this board (possibly disproportionate to the general population) is Asperger's. There also seems to be a good deal of narcissism, though perhaps not to the point where it would qualify as a mental disorder.