First, please let me say congratulations to you for getting off and staying off drugs. I imagine that five months in a rehab gave you a wonderful chance to adopt new ways of thinking and to apply them in the way that was best for you, individually. I believe that we all represent a diversified cross-section of beliefs, personalities, strong points and weak points....and who we are is based on the support structure we experienced from childhood to the present..from our families and friends. Some of us are lifted by religion, others by a faith within themselves. No one "makes" it without the care of loved ones in their life.....whether they find it from addiction groups and special sponsors....or from the awareness that close friends and family have seen them through their addiction...and are there, in the wings, with the love and support they need.
Just like "tough love" is appropriate counseling for some..while a softer approach goes further with others, there is no "one single path" in which we all find the answer. (And that's what makes the world so fascinating--there is so much diversity to explore!) :)
For a good number of former addicts, meetings are key to their survival. But there are others for whom a core structure of family and friends works best. Our earlier day-to-day life choices, are indicative of whether one-on-one straight talk is most effective--or if we thrive in groups of support. In the end...whatever works for YOU is the answer. And you may have to try both ways to find out. But my point is (yes! Somewhere in here is a "point"! LOL!) that your own decision--and your success in staying away from drugs--is a huge accomplishment in your life! And, it gets a high A++ from me...and a big, big "contratulations" to you on your success!! :D
As for your friend's sister--until she is ready to give up the drugs--there is no one thing that will help her. Talking, counseling, groups are all keys to recovery--provided she's listening. And from what you say, she hasn't reached that point yet. Other than the methadone, there is also a drug, Suboxone, that is fairly new....but gets high ratings from those who found it impossible to stop opiate use. Yes, it's a "drug exchanged for a drug"--but it produces no "high" from it....and teaches your brain to live without those ups and downs that have become such a part of your life. Those here who take it, say they feel "normal" for the first time in so many years. They do not suffer the terrible depression and lethargy connected with withdrawal...and they say that when they take Suboxone, they do not even THINK about seeking other drugs. You DO have to taper off it, when you ready to stop (athough some people stay on it for years), but I have not read any better feedback on any drug for addiction than I have with Suboxone. (You can check the Archives here in the Board's "Search" box.)
Anyway, you have done a wonderful job to change your own life. But, unfortunately, there will be a limit to how much you can help your friend's sister, until she wants...and asks....for help. It must be very disheartening for you--having come through your own struggle--to watch this unhappy young girl, who feels so hopeless about life. I do hope that there will be a happy end to this story. Please do keep checking in here. People do truly care. :)