Response to lithium different between and borderlines?

Hi just looking for some feedback. My 34 yr old sister has been diagnosed bipolar but some drs have suggested she might be borderline personality instead because she gets angry when in certain moods and has a history of abuse. Se has had chronic depression for maybe 15 yrs with mixed states and hypomania but mainly depression. No treatment has ever worked until she was put on lithium 3 months ago. All her symptoms have totally disappeared. She's not depressed at all and her mood is stable. We were told this can change later on but is this response possible in borderline people or more likely bipolar? I'm bipolar myself and on lamictal and I think she's bipolar and the anger is just part of it. But I'm open to hearing otherwise. I just assumed if she was borderline it wouldn't be as simple as taking lithium? How do non bipolars generally respond to lithium on its own? Her blood level is 0.9 last time I heard.

I don't know the answer to your question, but have you asked the borderline board?

And... WELCOME!

Yes, Welcome aboard. I would check with the bpd forum, and consider the possibility that she may have both diagnoses. I can be pretty hard for some docs to tell the difference between bp and bpd, but my guess is that if her symptoms resolved on the lithium, she's bp, at least.

I have both. A lot of ppl have both. I agree with Buggs - my guess is that she is has bp, at least, but the main point is: congratulations! A solution has been found! I am on Lithium and totally depend on it.