Originally Posted by Jarno

Borderline is known to be the most difficult PD to diagnose.

I know a girl who actually has been diagnosed with it. Some behaviours of her:
She sometimes call her ex boyfriend (a friend of mine) 50 times on 1 day. He never picks up his phone, but sees 50 unanswered calls on 1 day! If she talks about her ex, she talks about him as if he is a God. (=idealising partner). She has tried to commit suicide twice and has been hospitalized. THAT is borderline to an extreme degree.