[faeriechangling]

Don't know much about BPD, know a little more about schizophrenia. The genes that make you predisposed to schizophrenia seem to positively impact creativity and certain types of creative output. A gene doesn't necessarily have to have a good outcome for everybody with that gene, so long as it results in enough good outcome to make up for it.

I think of this with homosexuality. What is the possible evolutionary advantage to homosexuality? Well there's lots of reasons why we would want humans to be attracted to both men and women, so they're reproduce, and it's not hard to see how genes that cause that could make people gay.