My experience with teens (mine is just about there, but I end up as a surrogate parent to many each school year) is that you can't remove them from the poor peers. This is a control issue, and they'll usually just fight you, for the sake of it.
They need to alter their behaviour based on the peers they chose, but you can guide them. The trick is to have them paint some sort of future for themselves. Kids that only live for the moment seek nothing more than instant gratification, be it from drugs, alcohol, or whatever. Ones that see some positive future are the ones that can keep it together. My job at school, 99% of the time, is to help them create that future vision of themselves.
I'm not saying we all want compliant kids. Hell, no. They also do need to fall down and learn from their mistakes, but the trick is to make sure that the fall isn't a fatal one, or one that ruins their entire life. I left home at 17, and it was a positive thing in my life. I was also involved in drugs, all night parties, and lots of things that parents dread. But, as I got into the latter part of high school, I had this faint picture of myself in the future, and though it is far from the reality of today, it gave me reason enough to mature and take control of my life.
My daughter is not quite a teen, but even grade six students face massive peer pressure. But, she has a group of very close friends that do not attend her school, and share her love of climbing and skiing. These girls have an external focus that binds them together and creates very positive peer pressure. You have to stay fit and healthy or you let your climbing partners down. These friends are not the fair-weather friends in her class, but girls that that she has shared some of her most important experiences with.
The thing is that it takes a lot of time. Most families I know with a teen have taken advantage of the child's independence to go back to having two careers. The reality for most families is they require the incomes just to make ends meets, but it's also super important to make a ton of time to just be in the life of your child. You also need positive avenues of expression. My neighbour has supported her daughter's love of volleyball. Her teammates are her friends and they share a common bond that allows them to repel the burnout kids that might want to join in.
My own students are working towards a series of year-end trips, including a couple of back-country adventures. They have a goal, and they're working towards it. They have to learn wilderness cooking, first aid, navigation and other skills. They have to increase their fitness. They have come together as a group, and they actually have begun to exert positive peer pressure on each other. The eleven of them came on a field trip this week where three brought some booze. The other eight were outraged and have expressed their bitter disappointment. Five months ago all eleven would have been downing shots. But, they see something to work towards. Even the "roughest" kids like a positive goal.
No Judgment. This is difficult. My students (and my daughter) can tell me ANYTHING without the fear of repercussions. Yes, anything. Problems need to be solved, not punished. Punitive measures rarely, if ever, work. Using dangerous illegal drugs? Yelling and grounding and so has no effect on a 16 year old. They have a problem, and it needs to be solved.
