News that alcohol and marijuana use among teens is on the rise should be of concern to every parent—and every non-parent—in America. Starting out on a bad path too often leads to deeper alcohol and drug addictions, which have major impacts on society.

The Partnership for a Drug-Free America released a study showing the number of teenagers in grades 9 through 12 who say they drank alcohol in the preceding month increased 11 percent last year. Some 39 percent, or about 6.5 million teenagers, reported alcohol use in 2008—up from 35 percent, or about 5.8 million teenagers.

It’s not much better for reported marijuana use, with 25 percent of teenagers saying they smoked marijuana in the preceding month—an increase from 19 percent.

This is a trend in the wrong direction. Alcohol and marijuana use had been in steady decline since 1998. Given increased pressures on teenagers these days to fit into a society that is trending more and more toward what is deemed “adult behavior,” these figures may not be such a surprise. But they should certainly jar parents out of whatever comfort zone they thought they were in when it comes to their children.

Here’s the reality: Parents need to guide their children through the difficult stages of development, and they can’t really guide when they don’t know what their children are involved in. Just knowing what the pitfalls are isn’t enough; parents must know what pitfalls are immediately in front of their children, or what already may have trapped them.

The best guidance starts with trust and involvement begun in early childhood, nurtured and built through the years and maintained with teenagers, even when that’s a struggle and despite the inevitable difficulties as developing children test parental boundaries in an increasingly anything-goes culture.

Drug-Free America recommendations include close monitoring if parents suspect problems. It’s important to act quickly by having a conversation, setting rules and consulting outside help such as counselors, doctors or clergy.