Welcome Denise oefwalker: I'm so sorry about your family history and the situation with your sister. We all tend to have a BPD trait or two. Even people in families without history of personality disorders can exhibit a trait or two. The traits seem to come out during times of stress. Unfortunately, they are more often displayed behind closed doors, with family.
I know as a result of my parents behaviour I am a people pleaser and will avoid conflict at any cost. I know this sounds contradictory but I have tried to avoid clashes with my sibling for years but somehow I always seem to get drawn into arguments where I either lose my temper and get accused of being aggressive or try to stay calm and get accused of using psychobabble.
I am now at the point of cutting my sibling out of my life in a similar way I had to with my parent or I am going to lose my sanity. There is part of me that really doesn't want to give up on her as I now understand why she is like she is but she will not acknowledge she has an issue -apparently it's me not her.
It is very common for the family members of someone with BPD to seek therapy, but the person who most qualifies for the label of BPD to NOT admit that they have a problem or have any desire to change or seek therapy.
My sister has had her issues through the years, but displayed many of the classic BPD symptoms when our elderly parent's health began to fail and they both passed within 6 months of each other. I was painted black by her (
(BPD BEHAVIOR: SPLITTING). My sister went into rages in my presence, called me names, told me everything she hated about me, gave me the silent treatment and argued about everything. She would complain that I was either "talking down to her" or "talking to her like I would with someone I worked with" (which I believe she saw as over her head).
We can't change them. We can only control how we interact and react with them. Lessons about
BOUNDARIES and
AVOIDING CIRCULAR ARGUMENTS are two good places to start. There are, also, links to helpful information to the upper right of this post.
Have you read any books about BPD? It took me going to therapy to help me figure out what was going on with my sister. After a few sessions, my therapist suggested I read the book, "Stop Walking on Eggshells". That was the book that lead me to this website.
One approach would be to try some of the communication skills with your sister and enforce some boundaries. There are a lot of helpful people here, and it can be beneficial to try some of the strategy form lessons and gain the input from others who are using the same skills.
The decision to go NC is a personal one. Just because you make that choice, doesn't mean that you can't change it in the future, or go to LC (limited contact).
Check out the tutorials on Boundaries and Avoiding Circular Arguments at the above links and let us know what you think.