I posted on another thread, but thought it might be better to start my own:

My sister has been going through tough times; it always seems like things happen to HER. The crazy boyfriends, psychopath bosses, getting stolen from and used over and over...it's like she can never win.
She's never gotten along well with our mom, and I share the Can't-stand-my-mom-if-we're-under-one-roof syndrome that many women have, so i thought it would be a good idea for us to pool our resources and get a house together. Now that i live with her, i catch her lying about so many things -

I confronted my sister last night, and had to show evidence after evidence that i knew she was lying, as she slowly adapted the story to fit what i knew. but i still wonder, if her story about her ex attacking her is true, why it took 2 weeks for the knife to turn up in the kitchen again... I suppose i might never know what actually happened that night...

Anyway, i fell i made it clear that this behavior will not continue in my house, that i feel disrespected, and i'm not willing to live in a household where i have to stay home to make sure no shenanegans are going on. I told her that i suspected her of self-harming, and that if ever i caught her lying to me again, we would part ways. Finally, I reminded her that she needs to love herself and follow her instinct to do what she knows is right, and if she can't plant her flag in her own home and speak what's really on her mind to her sister, then she is not taking advantage of the opportunity she has to change and create the life she wants for herself. And of course i told her that i love her very much.

Unfortunately, I still feel like i'm waiting for the other shoe to drop...
Is it possible to help her? She's run through a hospitals, boarding school, therapy and refused further counseling. Am I wrong to think that I can help?

Well, i think it's time for an update -
Since the last time i posted about this, i really haven't felt that much has changed.

One conversation we had did center around the fact that since i can't trust her judgement of who is a good person and who is trustworthy, and i can't trust her to be honest about what happens when i'm not home, that i think it's reasonable to say she can't invite friends to the house. At first she said OK, then she said she might have to "consider other options", then we talked and she said OK again... What that seems to boil down to is that she doesn't tell me anymore if she's not coming home for the night.
More and more often, I recognize the ways she's her own worst enemy, and sure, I can understand that this is typical early 20's behavior. BUT- I end up taking care of her dog when she's gone with no notice, I find collections notices on the table and she confessed to self-harming. Also this weekend, I explained to her it was very important for her to be home in the morning on Saturday and Sunday to hold a garage sale, she agreed and promised to help me, but both nights she stayed out all night and was worthless the next day. Her alibi for why she couldn't come home was blown saturday morning when she invited a colleague over, who made a comment that didn't jive with her story.
Sunday morning, we woke her up because someone appeared to take her to go get her car - we found her 30 minutes later checking her e-mails, while the friend was still waiting for her outside! She was still so smashed that she started to argue with me that she had driven herself home.

So when she to me on sunday night, "Hey i'll be home tomorrow, leave me a list of what you need me to do", the only thing i could think to do was leave a legal document for her to sign to get her name off the house.

She's tried to tell me i'm being unfair, and that she's "normally so mature for her age and unusually responsible" that my expectations are skewed, and i'm getting mad at her for just being "typical".

To what extent am i supposed to accept "typical youngster behavior" as an excuse for having additional responsibility on my shoulders and worse - her still lying to me about it?

Ok let me ask you, you said you pulled your resources together to get a house, does she pay her part?

If she pays her part you cant complain. Her name is on the house just as much as yours is so why do you get to dictate what she does? its not fair for you to tell her what she can and can not do, she is an adult. To me you sound like my sister and I can tell you that I put in my part & yet the control was what ultimatley seperated us. To this day I cant stand being around her and feeling like she is trying to control my life. Be careful with what you do because she doesnt need another "mother"

Also about the young thing, yeah its true to a point. She is young and having fun. One day she will grow up and become responsible, let her do it on her time. Let her learn how to be a productive part of society. Her problems are not yours to own so let them stay with her.

I know that this disrups your life but this is a choice you made. Maybe it is time for you to split and be friends living apart. Living with my sister ruined everything. to hear her tell me who I could have over, when I could eat, what I could eat, what I HAD to do, when I HAD to do it, got really old and now I hold a lot of resentment for her.

She is an adult, you cant treat her like a child. As long as she is paying her part then you need to keep your mouth shut.

On the other hand if she isnt paying her part then tell her to move out.

Thank you, you have some valid points-

Yes, she's an adult. She has her own job, her own car, we keep our own schedules and have our own friends. We operate very independently.
However, the drama she brings to the house has escalated to the point that it directly affects me. We got kicked out of our last apartment due to altercations between her and her ex that resulted in police involvement. (I question the legality of what the company did, but my sister was unable to get a copy of our lease from her employer, who was the same management company)
I've heard from the neighbor that police have come to my house while I was out of town, and when I came back this last time, she asked me if her most recent ex (the one who supposedly attacked her) has returned her dog yet. Am I wrong to feel uncomfortable about that?

I haven't had any objections or put any restritions to her bringing people over until I found out that she lied about what happened when she got cut. For the past year, she's been free to and has invited over friends, boyfriends, hosted parties, her b/f moved in, and his kids stayed here many times. With all of this there were no problems - I simply asked to be informed if there was a party. In fact, there were times when I didn't come home, that she called ME to remind me that we're supposed to check in every 24 hours. So, no, I don't think that I've BEEN in the mothering role the whole time we've been living together.

She did not contribute to the down payment, which is okay - we agreed that amount would be settled at some future time when we split ways, though I didn't think it would be so soon.
She does pay her part of the monthly bills... eventually... after I pay all the bills up front and then tell her the total. She was initially in charge of one utility bill so the responsibility would be more balanced, but it never was paid and now has a $1000+ balance.
Major repairs had to be done to fix the sewer pipe when it backed up 8 months ago - she hasn't paid her half of that yet.

I'd like to have the liberty that I afforded her - to have my boyfriend move in, but that's not realistic in this situation.

So as I write this, I think it's obvious that I do already harbor resentment for what's happened. She probably does, too. And sure there have been times when we were talking that I've caught myself giving advice. Although, friends give advice that no one listens, too, as well. And, really, How am I not supposed to say "take care of yourself" when she's got a foot long cut from her face to her neck?

So if I don't want to live with her anymore, I don't know what I'm supposed to say. Do I start with "I don't think our relationship is going well with us living together anymore. We need to find other options. Do you have an interest in buying out my half of the house?"

I understand what your saying and your frustration. I guess what I would do is just let her know that you believe that your relationship is better off not living together. Let her know that you fear that if things keep going the way they are that guys will end up hating eachother.

Trust me, living with a sister is hard and it creates a lot of problems. Like I said yesterday I hold a lot of resentment for my sister and I never knew until yesterday.

My father is in town and my sister wants to spend all her time with him, which I completely understand (he is staying at my house) but you put the two kids together (mine and hers) and its just crazy. Well I still have a life of my own and I feel that my husband & i deserve to have time alone when my dad is busy with friends. But my sister thinks that its ok to just sit at our house and wait for him which disrups what we need to do, not to mention that we are strict with our daughters bed time, where as my sister could care less what time her son goes to bed. So this has been bothering me and driving me nuts for days. I have always bent over backwards for her and done everything she askes me to do but now I am tired of it so I have started to put my foot down. Well last night I got home and I was just so mad thinking about all the events in the last couple of days. Well I broke down and just told my dad how i feel. I feel like she has taken advantage of me, used me, disrespected me and the list goes on. She to lies all the time and it bothers the crap out of me and that is why we split 4 years ago. Its been 4 years since we lived together but everything that happened back then has stuck with me and its building inside of me.

Sometimes we are better friends with people if we have a gap between us.

Thank you for sharing your experience.

I wonder how you've tried approaching these more recent "misunderstandings" with your sister - like when she's sitting around waiting for your dad?
Have you tried saying "I enforce certain rules in my house for my son/daughter, and it's much better if all the kids abide the same rules, and those rules should be upheld by all the adults - so I need your help in this way..." and hey, it's your house. You expressed that she didn't have a problem telling you what to do when you lived together years ago. If you have tried that, what happened?

One thing that I do feel is kind of odd is that my sister often calls me to find out when i'm going to be home, but then she usually is not home, or is on her way out when i do get home from work. She sometimes calls me from her work (at a bar) to see if I have plans for the night, if I'm planning on staying out. And when I say I'll be home, she tells me how much she misses me, but then doesn't come home until well after the bar closes. She's suggested that we keep a weekly calendar so we'll always know where the other is - I couldn't help but make a snyde comment that she only wants to do that to make it easier to avoid me, she ignored it.
She's also sent me txt messages, "you're my favorite sister ever! Shhh! It's a secret!" (there are 4 of us girls). And if I don't reply that I love her, too, she can get pretty upset. This happens right after a fight, or when something especially good happens. Or she will txt me little things - like "I wonder if I should open the windows and air out the house today? Do you think it will get hot?" - when just an hour before, I had seen her at home and we barely exchanged 5 words. Usually, I would think that she's trying to reach out and connect with me, but since I don't think she wants to address what caused the fight in the first place, I feel like responding would reward her for "playing nice" and avoiding the real problem. So I'm inclined to blow her off - which is also unhealthy for me because it means i'm holding a grudge. Did you run into this scenario, as well?