I can't post links yet so I'll put the beginning of this article and I'm sure you can Google it if you want:

Big Psych trying to sort out the details of the things they made up. Bipolar I is like schizophrenia, its a genetic mental difference. Bipolar II/BPD may be influenced by genetics but it's as much a personality type, with strong genetics for moods, but not actually manic-depressive bipolar.