Parenting a teenager has never been an easy job. Almost overnight, parents watch the child they’ve raised since he was a baby turn into a loudmouthed, angry, moody, almost adult. Communications during this time can be extremely difficult and explosive, if possible at all.

Adding to this explosive emotional soup is the fact that teenagers think they know everything and are indestructible. Not surprisingly, this can lead to trouble at home, at school, and worst of all, with the law. But, as most adults can remember, most teens are going to get into some sort of trouble, that’s just part of growing up. So how can a parent differentiate between troubled teens and normal teen struggles? And when should a parent seek help outside of the family?

Here are some of the warning signs that your teen may be in trouble that goes beyond normal teen antics and how to address it.

Has your child stopped hanging out with old friends and started hanging out with a whole new set of friends? On its own, this can be a normal part of growing up. Be sure to get to know your child’s friends and gently let them know that you are involved in your child’s life. If your child is not letting you meet her new group of friends, this could be a sign that she is trying to hide something from you.

Another important indication of trouble is a drop in grades and interest in school. This does not mean that you should start drug tests if your child gets a “C” in calculus. But it’s not normal if your enthusiastic and helpful student suddenly stops turning in homework. Be sure to keep in touch with your teen’s teachers both during the conference and throughout the year.

Mood swings are another normal part of adolescence, but extreme mood swings are not. Extreme mood swings can be a sign of major depression. Signs of depression can include changes in eating or sleeping habits. Teens who suddenly drop out of social circles and extracurricular activities may also have problems.

Treatment for depression can be as simple as a few sessions with a therapist or a prescription antidepressant medication. In some serious cases, doctors may recommend that parents seek therapeutic internships.

The teenage years are frustrating for everyone involved. But parents who keep an eye on their children’s behavior and take action when they see signs of trouble will be glad they did.