Signs to Watch for to Tell if Your Teen is Using Drugs

Angry looking teen

In a dozen years of working in this field, one of the most common phenomena I’ve come across is parents who don’t realize that their teenaged or young adult child is using drugs. It’s easy to miss because there are a lot of changes going on during these years. Are the dramatic changes being witnessed because of the challenges of growing up or are they because this young person has started using drugs? Or worse… because they have become addicted?

When there are behavioral changes or the young person’s appearance goes through a dramatic transformation, it’s tempting to simply chalk it up to adolescence. In today’s world, however, that could be a mistake. There are so many different drugs around that a young person needs a parent’s constant monitoring to make sure he or she can make it to adulthood sober. According to research, if a young person makes it to 21 without ever drinking or using drugs, they are nearly certain to avoid serious problems with drugs in their later years.

Before we get to the list of signs, please give this concept some consideration: No matter how much you trust your child, no matter how busy you keep him or her, no matter how sure you are that your beloved child would never use drugs, you still need to be vigilant for any signs of drug use.

There are simply too many parents who wish they’d known earlier that their child needed help. And there’s too many parents who have been blindsided when they discovered that their beloved child has been addicted for years.

Just to clarify, no one wants you to become overbearing or inquisitorial. Rather, you need to simply be alert to the constant threat facing your children when they are at school or otherwise away from home.

Imagine this scenario: Every day, your child visits a hospital full of children with contagious diseases. You would watch that child closely for any signs they are getting ill. Unfortunately, that is the kind of vigilance needed to ensure your child stays drug-free and alcohol-free.

Here are the signs you should be watching for, sorted into categories.


  • Grades declining or plummeting
  • Previous academic goals or interests vanish
  • Classes or whole days skipped
  • After-school activities that used to be enjoyed are abandoned
  • Repeated disciplinary actions
  • Teachers comment on a change in the student’s behavior or study habits
  • Future academic plans such as college no longer interest him or her
  • Assignments are late, not turned in at all or are poorly done


  • Young person changes his set of friends, perhaps after arguments or upsets with prior friends
  • New friends may not appear to be successful in life
  • This person and his friends never seem to do anything productive or educational
  • New friends are unwilling to meet or engage with other members of the family or are sullen or disrespectful when they do

Physical/appearance changes

Teen with a headache.
  • Young person is no longer particularly interested in or willing to maintain cleanliness or grooming
  • His or her style of dress changes dramatically
  • Skin roughens or looks unhealthy
  • Individual complains of one health problem after another which could include diarrhea, constipation, stomachaches, headaches, tiredness, anxiety, inability to concentrate, trouble sleeping


  • The young person’s room and belongings are neglected, messy or dirty
  • Possessions that used to be treasured and cared for are ignored, damaged or missing


Of course, when a person starts using drugs, their usual mood is going to change. But because they don’t want anyone to know about the drug use, they are going to conceal this change. Many will try to act the same around their family members so no one asks any questions. This is where you are going to need to be very sharp. You’re going to need to be alert to the small giveaway signs as well as ones that might be more obvious.

A lonely teen can’t communicate with former friends.
  • The person’s attitudes become less positive
  • Relationships with other family members deteriorate
  • He or she begins to be argumentative and oppositional
  • Ability to grasp complex concepts is poor
  • Person forgets chores, responsibilities, appointments
  • Minor legal problems start showing up and escalate into larger ones
  • Money goes missing, loans are asked for
  • A normal desire for privacy changes into isolation and secrecy
  • Personal possessions are guarded and hidden away
  • The person may object violently if anyone goes through his clothes, pockets, backpack, vehicle or other possessions
  • Person is simply missing much of the time and won’t account for his whereabouts
  • Family or school events are skipped
  • Excuses are made for failures in responsibly or performance, over and over

Of course, a person may show many of these signs and not be using drugs but simply be struggling academically or socially. Or he (or she) could be hanging out with a new group of friends who look successful and sound friendly but are all into some new kind of drug. The variations are endless.

The dangers are so intense that the first thing you must do is completely forget about being naïve. Be loving and caring as always, but vigilant. Make sure that excuses really do make sense and follow up on some of the stories you are told about where money or possessions went or why friendships ended. Sometimes those friends know more than they let on but are afraid to say anything.

Don’t let your love and desire to trust this person you love so dearly blind you to the possibility of drug use or underage alcohol use. There are simply too many youth being caught in this trap while they are living at home or away at college or working their first jobs. By catching problems early, you might save him (or her) years of anguish and possibly even save his life.


Karen Hadley

For more than a decade, Karen has been researching and writing about drug trafficking, drug abuse, addiction and recovery. She has also studied and written about policy issues related to drug treatment.