Adoption Support Group

This sounds like the last thing you'd want to do but, you might want to consider that she needs to openly express her feelings about being adopted, tell her that her anger is okay, because it is part of the grieving process for losing her first family. Its hard for adopted children to accept and fully come to terms with their new families love if they havent fully grieved the "rejection" and loss of their first family.

Your sister may have a personality disorder or some other psychological issue that is exacerbated by her being adopted. I sure hope your family is in therapy.

maybe she is testing the boundaries
if she was 7 yrs old when adopted that would have been so hard
i think she is testing your family and she may not even realise it
and what i mean is that if she does all this and you all still love her maybe she will not be rejected by you as well
the rejection of being seperated from ones birth family is very very painful
how she must feel
will it happen again
will it happen if i do this testing you
hope i have explained this well
and yes she may have a few problems but who wouldnt being rejected at 7yrs old when you have time to know your birth family
and this doesnt mean she doesnt love you
she is also probably going through those hard teenage years and i think everything gets a magnified then
if there is anything you can do i woould assure her of your feelings for her
they may seem to be received on deaf ears but they will stick and one day she will feel more secure