Work! Get a job stupid!
One of the ways we have helped underachieving and or teens who were doing drugs or involved in at risk behaviors has been to require them getting jobs.
When they learn they can:
1. produce,
2. make their own money,
3. have more control in their lives,
4. not be dependent totally on parents,
5. think about the value of money when idiot "friends" want to borrow for drugs or whatever.
It makes all the difference.
This works for teens from very wealthy families as well as teens from poor families.