According to my daughter, this indeed happened. On top of that, some of the people they know are dangerous and threaten them. Many times before she quit, she wanted to quit, but was scared back into using and even selling. She had to leave the state.
BUT....
A determined drug user can and will make druggie friends wherever he/she goes. It takes a determination NOT to hang with those types anymore and can be very lonely as they try to switch to another type of lifestyle. Often, Daughter was lonely. But she was also determined. And she is pig-headed. Nobody was going to suck her back in. However, if she had stayed home, in our house, she would have been surrounded by those who had encouraged and threatened her to use and sell. According to her, and I can't validate if it is right or not, if you use, you sell. She was clean by the time she told us her story, which shocked us--we had no idea she had used so many horrible drugs--we had figured it was mostly pot. Not so.Speed was her thing. ADHD drugs crushed into pillcrushers and snorted with or without cocaine. Ecstacy. Meth. Yes, meth. We hadn't even gone there in our minds, my husband and me.
The drug life is hard to leave. They welcome you with open arms until you make noise about quitting. That's why your adult child is probably not clean if he/she is still hanging with druggie using friends. You are not allowed to co-exist beside them without also using. Plus like attracts like. People who don't use have no interest in users. My daughter is now, as s he calls herself, "a boring housewife and mother." After she had her baby, she quit her job and is nothing like that wild child she used to be. Right now, she takes no drugs and it is even hard to get her to take an Ibuprofen. She is an "all natural" girl as is her boyfriend (only he is not a girl...haha).
The baby eats all sorts of stuff that most little ones don't like....she totally loves veggies and fruit without sugar...it is amazing. They don't allow anyone to smoke in their home. They almost never party or even drink, although they do drink once in a while, but not to get drunk.
I think the drug addict has to be in the state of mind to give up h is lifestyle entirely in order to quit. You are literally changing what you do, who you interact with, and making a decision to join society.