Teen substance abuse is one of the most serious problems in our society today. Although teenage drug abuse has declined since the high it hit in the 1980s, it is still an issue affecting every community. As drugs of choice continue to evolve for teenagers, parents often loose track. Nowadays, you don't have to worry about teen cocaine abuse as much as you have to be concerned about crystal meth addiction. You don't have to worry about your child injecting heroin necessarily, but you do have to watch out for ecstasy. The connections between teens and substance abuse will always be changing and never completely go away, so parents have to stay on top of it.
A lot of people take the wrong approach to teen drug abuse. Many parents believe that their duty as parents is to try to catch their teenagers in acts of wrongdoing. This is a wrongheaded approach. You should talk to your child about teen substance abuse, but you should not treat him or her as a criminal just because he or she is a teenager. Teenagers deserve a measure of respect, and they should be given the benefit of the doubt. If you've no reason to believe your kid is using drugs, don't treat him like a drug user. Keep an eye on the friends he keeps and on his actions, but do not make him your enemy.
That doesn't mean that, as a parent, you don't have to watch out for the symptoms of teen substance abuse. On the contrary, you need to be ever vigilant. There are certain drug specific indicators such as red bleary eyes, frantic speech, or paranoia, but there are quite a few broader markings of teen substance abuse. If your child changes the friends he is hanging out with, seems withdrawn or suddenly secretive, has mood swings which are unusual even for a teenager or start slipping classes in school, you may have a teen substance abuse problem. At that point, you need to check in with your kid and make sure everything is going alright. Treat it as a friendly conversation. Don't get paranoid and don't accuse him of anything.
There is a time, however, when you have to act. There are plenty of substance abuse treatment facilities for teens out there, so when talking doesn't work or when you are sure your child has a problem, you do need to get him in for treatment. You want to do it before he gets into trouble with the law if at all possible. Once police are involved, it gets much more difficult. The state will start to question your ability to even be a parent, and may take the child away from you.