Your daughter has a new boyfriend. He seems nice enough, but thereâ€™s something about the way he talks to her sometimes that makes you worry: is he as nice as he seems?

Teen dating violence is a real problemâ€”and itâ€™s not rare. One in five adolescents report some kind of violence (including psychological)â€”and up to one in eight report physical violence (girls are more likely to experience physical violence than boys). Think about that: in a high school classroom of twenty kids, that would mean four are in an unhealthy relationshipâ€”and two of those four are being beaten.

A study just released in the journal Pediatrics gives us more reason to worry; it says that young adults who experienced dating violence as teens were more likely to be heavy drinkers, smoke marijuana, be antisocial, be depressed, and think about suicide.

Not what we want for our children.

What makes it hard is that itâ€™s not always easy to pick up on dating violence. Abusers can seem remarkably charming. Victims can be reluctant to admit itâ€™s going onâ€”and often are made to feel like the problems are their fault, not the fault of the abuser. Even signs that should seem obvious, like bruises, get explained away (â€œI fell at school.â€�) So parents need to be very watchful, and ask lots of questions.

Here are five signs your teen might be in an unhealthy relationship (Iâ€™m saying daughter here, but it could be son too):

He doesnâ€™t always treat her with respect. This sounds obvious, but itâ€™s something worth thinking about carefullyâ€”because we can sometimes dismiss small things we shouldnâ€™t dismiss, both as victims and as onlookers. Does he belittle her? Does he make fun of her in front of others? Does he say unkind things to her about how she looks, what she does or what she says? Does he show up late, or bail on her, or not call when he said he would? Each time it happens it may not seem like a big deal, but if itâ€™s frequent, it is a big deal.

He smothersâ€”or otherwise acts obsessed. It can seem sweet at first when he calls all the time or wants to be with her every moment. But when it doesnâ€™t let up, and when it starts to get in the way of your daughter seeing friends or doing activities she likes to do, or when he wants to know what she is doing and who she is with all the time, or if he is often jealous, itâ€™s a warning sign of problems.

Your daughter changes her habits for him. We all like to please our partners, and a few changes arenâ€™t badâ€”sometimes they can even be welcome (like starting to wear clean clothes regularly). But in a healthy relationship, each person appreciates the other for who they are. Itâ€™s not good if your daughter suddenly is wearing different clothes (especially if they are sexier), is giving up friends or activities or is otherwise acting in ways that are, well, just not her.

He hurts her physically in any wayâ€”or she has an unexplained injury. Ask questions. Make sure the story makes sense. It is never, never okay for someone to physically hurt another person. Sometimes when we are in the thick of it, we lose track of thatâ€”but itâ€™s a really important message to teach our children.

Your daughter seems more sad, irritable or anxious than before. Healthy relationships make us happier. If we arenâ€™t happy, there is a problem.

If you are seeing any of these things, sit your teen down and talk. As upset and even angry as you may be, talk to her in a loving, supportive way. Be patient, and be ready to try again if she says there is nothing wrong. It can take a while for someone to be ready to talk about these things.

To learn more about teen dating violence and what you can do about it, check out the Teen Dating Violence page of the website of the Centers for Disease Control and Prevention.