If your child were smoking, would you know? Parents in classic family sitcoms only found out when they smelled smoke on their daughter’s breath, or a cigarette pack fell out of their son’s jacket. I suggest taking a more assertive approach to stop teen smoking before it starts.

As parents, we need to know what’s going on in our children’s lives. Sudden shifts in their emotions, behavior or social situations are early signs of trouble. As the advisor for the TalkEarly, Talk Often, Youth Smoking Prevention Program, I’ve developed several tips and strategies that can help parents spot problems and better communicate with their children. The following are five warning signs exhibited by kids who may be smoking or thinking about experimenting with cigarettes:

Trouble Communicating – Getting children to open up about important topics isn’t always easy, but talking early and often is the best way to keep them from smoking. Teaching your kids to make the right decision about smoking builds the foundation for open communication on other tough topics.

Friends Who Smoke – Peer pressure can be a powerful force when kids are constantly challenged to fit in. Let your children know you remember what that’s like, but stay firm in your efforts to keep them from smoking.

Sinking Grades – When children stop taking pride in their work and their grades slip, they may be struggling with more than just math and history. Kids trying to be rebellious sometimes neglect school work, and may also try smoking. Instead of judging their poor marks, talk with your kids and their teachers to find the source of the problem.

Lack of Interest in Activities – Children who are active in school and community activities are less likely to light up. Encourage your kids to participate in clubs, sports and other pastimes without being pushy.

Low Self-Image – Kids sometimes get down on themselves, but if they lack confidence in their abilities, fail to take responsibility for their actions, or turn away from love and support, there’s a problem. Children with low self-esteem may sometimes turn to cigarettes to feel cool. To help kids stay positive, share your own experiences and keep a positive attitude.

For more information on teen smoking, check out KidsHealth.org.

Dr. Michael H. Popkin has spent 25 years helping families communicate about tough topics like smoking. He is also founder of Active Parenting Publishers, and author of many award-winning parenting education videos and books, including the recently published Doc Pop’s 52 Weeks of Active Parenting.