Lots of issues going on here, morally and legally. I'm not sure which part you've asked about, so I'll tread carefully until I understand more.

If she is 18, she knows wrong from right. And being bi-polar, she knows she needs to be taking the meds. This 18-year old is making radical decisions and has no regard for the Mother. It can only get worse without the meds, or possibly, I should say.

She has to be held accountable for her actions at some point. If it were my child, I think I would report the car stolen BECAUSE I would want to know where she was and if she was okay. Right now, without sitting and hoping for the best, I think it would be my only alternative.

If she was arrested, then at least I would know she was safe and could force her to take the meds. Or at least try. Because she is OFF of the meds, her thinking is not clear MAYBE??? I have to say that this would be a heavy factor in my actions but really, what other options does the Mom have, other than sitting and wringing her hands? Of course if she is arrested, she'll have that record from now on and because she is an adult, what are the penalities? I would have to know that before I made that decision.

There is always more background than what you've given here ... things leading up to her behavioral changes, life, situations, etc., so giving a lump answer is hard to do without knowing them personally.

But I will tell you this. I do believe in tuff love. At some point your sister needs to think about HERSELF as well. Our children can make us crazy with worry, they can break out hearts. We have to love them enough to make them responsible for their actions.

I sincerely hope she comes home safe and sound. My heart aches for your sister because it is very easy for me to put myself in her place. I was one of the lucky ones as my own push the envelope when they were young, but came out on the other side unscared and safe, and as responsible young men. Thank you God! So I empathsize with her.