Oh, lots of good advice has come before me, and I don't know if I have anything to add, but I'll tell you my story. My son started using when he was 14 after his dad and I got a divorce. I noticed his grades dropping, his attitude and friends changing. I tried to get him into counseling right away but met with delays. He was taking robitussin and dramamine, commonly called skittles and smoking pot. We tried a 30 day program, he came home and after a few months he was obviously actively using. He tried rehab 3 more times before he finished successfully. Along the way, he graduated to using alcohol because it was easier to obtain and hide. I have had him arrested, seen him in the orange jumpsuit twice and now he is back in rehab for a 5th stay. Every time he goes to rehab, he learns new ideas to help him and some day he will get it. I know that he will turn 18 next May and my ability to get him help will lessen so I keep trying. It's heartbreaking, sad, horrible. But I know that my son will always know that I loved him enough to believe that he could get well. Good luck with your son. REad all you can about addiction and codependency, Pray often, talk to good friends, and go to alanon. I wish I was there to give you a big hug.
krhea