BPD or ASPD?

Open Question: Borderline Personality Disorder or Antisocial Personality disorder? Both?

I'm worried about my best friend, she's been hospitalized twice and one of them diagnosed her with a personality disorder but didn't say which one, so I looked into it. I think she could be a sociopath but it's very likely she's borderline. She's never really seemed to feel guilty about anything though she tells everyone she does so that no one suspects anything, she confided in me that she has no conscience only an intellectual knowing of what is considered right and wrong, she tortures animals, sets small fires that peter out before they cause any harm, she has really bad anxiety when it comes to poisonous substances and venomous bugs, socially she's very eloquent and cons those around her.

She tells me she can love but I don't think what she's talking about is some form of sadism, which brings me to her being a sadist - she loves power and often she enjoys seeing others in pain, she looks at gore on the Internet for fun. It's sick, I've seen her laugh at the stuff. She's a hypochondriac and constantly thinks she's sick. She has a tendency to talk about others as if they are inferior and even says so herself, she thinks the world is centered around her. She used to cut herself and she says it's because she liked the feeling and she was angry.

Sometimes she'll yell for like no reason and get overly excited about little things. She has changed her style like every other month saying she's emo or punk or butch (she's a lesbian) or sometimes even a boy (she thought she was a boy for a little while) she hears voices that tell her to kill herself and others, she keeps on about how she wants to kill everyone at her school and because of this anger has to go to a new school. Everyone around her worships her but I see around it.
She used a lot of drugs and she says she misses the lifestyle and she's always pulling pranks and messing with people. When you disappoint her she gets really angry and upset, and when she's happy she seems to be crazy. She hates a lot of people and doesn't care about other's problems. Sometimes she appears to be very emotional and other times she's cold and has no emotions, what is this?

Why is it a "or" question, it's perfectly possible to have more than 1 PD. It sounds like here pathology is quite complex and serious and what with the sadism, animal torcture, fire starting and lack of guilt possibly dangerous.

I agree. People can sometimes have traits of more than one or even mulitple personality disorders. Cluster B disorders can exist on a spectrum - BPD, HPD, NPD AND ASPD and there can often be very blurred disttinctions between where one disorder ends and another one begins. For instance, her lack of identy and emotionality could fall into the BPD spectrum, her attention seeking into the HPD spectrum, her feelings of entitlement and superiority into the NPD section and her lack of remorse and affection could fall into the ASPD spectrum. As she has been diagonsed as having a "personality disorder" with no specifics this could certainly be the case. Of course I am speculating here, based solely on what you have told me, and am in no way qualified to make a diagnosis. That is a job for her professionals.

What you can be certain of is that, without intensive therapy and psychiatiric intervention and a desire to take responsibility, she won't change. What you see will be what you get. In her case, from what you have told me, she sounds unstable, unpredictable and possibly potentially violent. People with such severe issues, who are not prepared to take responsibility for themselves can very often drag their friends down with them in such a way that their personal boundaries can become blurred or even violated. There can be long term financial, emotional, practical and psychological repercussions for the friends and partners who become enmeshed. She has to take responsibility for herself and if she is unwilling or appears to be unable to do this, you may need to keep your distance.