I have a friend who may have a psychological disorder. Bipolar disorder seems to run in her family, but I m not sure that s it. her symptoms don t seem to line up with what I m reading. She has become hostile to her brother and me since we started dating about 4 1/2 months ago. He has noticed a pattern every 3 weeks or so of her yelling out horrible things about me in the street, slandering me among our friends, and just being disagreeable in general when my name is mentioned. (Keep in mind that this is a brother and sister we re talking bout, not a husband and wife--although they ve pretty much had no one but each other since the 80 s, and I realize she must feel threatened by me--even though I love her dearly and wouldn t hurt her for the world). Lately, her behaviour has been escalating. She has started stealing from me (perhaps more than I can prove), and we think she was throwing rocks at my window a few nights ago. She has burst into my home unannounced and screamed at us, and even threatened me this afternoon when the three of us were going out to do errands together. The threat was veiled, but I felt it. Her brother is really starting to worry, and even our friends have noticed--people who have known her way longer than I have--and come right out and told her that she needs help. does this sound like bipolar disorder to you? If not, what else could it be, and how do we help her deal with it? Oh, and did I mention that she has been telling me that our friends really aren t my friends--that they ve been gossiping about me behind my back, that our landlord, who has never been anything but kind to me, said I was a slut? What if her behaviour continues to escalate? Should I be afraid for my life, her brother s, or anyone else s--including her own?