Hi regine,   You are not alone, so many family members have the same problem you do.   In the U.S., the criteria for forced treatment, as sunfire told you, is that the person is a danger to himself or someone else.  There is one thing that you will not want to hear but it could happen.  You cut your sister off your mother's checking account, the sister can't pay her rent or motel fee, and things get worse.  She is then a danger to herself because she can't care for herself.  There is always the route to go of exaggerating the danger she is to herself, even now, even if she's not yet a total danger to herself.  Is she showering?  Eating?  Sleeping?  Try to find out as much as you can so that you can make the case that she is a danger to herself, before things get out of hand.  Unfortunately, because of the anti-psychiatry contingent who expect civil liberties at all cost, there's a strong resistance to forced treatment in the U.S.  Also, in the U.S., getting someone into a hospital and treated with meds is hard to do.  Often, it gets worse for the person and his or her family before it gets better.  You do not want to hear this, of course.   One option is to offer to pay her airfare for her to go back to Europe.   I recommend in cases where the person doesn't believe he or she is sick, that the family members read the Xavier Amador book, I  Am Not Sick, I Don't Need Help which coaches family members about how to talk to a loved one to help them decide to get treatment.  By the way, you are community member #23 that I've recommended this book to.  So many people ask questions about loved ones who refuse to take meds that I have been keeping a running tally of the number of times they write in and ask this same question.   I hope your sister is able to return to treatment soon.   Regards, Christina