Unfortunately, teens don’t come with instructions.  They are under enormous pressure and in very different circumstances than teens 20 or even 10 years ago.  This helpful site suggests many ways parents can be their teens’ “anti-drug” – including by talking with them and supporting them in appropriate ways.  Their site gives details on the stresses bearing down on your teen’s shoulders to help you better understand your teen and offers advice about what to do if you think he or she is using drugs.  theantidrug.com