[epicdweeb]

If you obsessively think about someone all the time are you likely to have this disorder? You don't act upon it, so the person doesn't have any idea that they're even on your mind, but no matter what you do you just can't get them out of your head. It's like the from the moment you wake up in the morning to the moment you fall asleep at night they are there, invading your thoughts, and you can hardly concentrate on anything else.

[easy goer]

It very well could be a symptom but be very careful it could be symptomatic of a lot of things. I know that my wife (BPD) engaged in this sort of thinking when she was in her late teens, as she showed me her diaries and it was just a real bad obsession with someone. So my guess is that a very strong obsession could be part of BPD but it also could be part of other things. Read the book Stop Walking on Eggshells or some other reference material and see if this person is doing other behaviors if she/he is doing 4 or 5 sorts of things that have no other explanation then maybe you are onto somethign.

[epicdweeb]

Thanks. I'll be sure to check out that book.

I'm guessing this people obsession along with feelings of emptiness and boredom, being easily angered, morbid thoughts, self-hatred, and frivolous spending could very well be BPD.