Quick overview: The most common signs of drug use in teens fall into four categories: behavioral changes (secrecy, mood swings, new friend group, declining grades), physical signs (bloodshot eyes, weight changes, unusual smells), changes in personal habits (sleep disruption, appearance changes, missing money), and direct evidence (paraphernalia, smell on clothing). Any single sign on its own may not mean substance use, but a cluster of changes that lasts more than two weeks is worth taking seriously. If you’re worried, the next step is a calm, non-accusatory conversation. Our helpline can help you prepare for it.
In this article:
Figuring out if your child is using substances can be challenging. Many signs of drug use in teens are typical young adult behavior. Many signs of drug use are also symptoms of mental health issues, including depression or anxiety.
If you have reason to suspect use, don’t be afraid to err on the side of caution. Prepare to take action and have a conversation during which you can ask direct questions like “Have you been drinking, vaping or using drugs?” No parent wants to hear “yes,” but being prepared for how you would respond can be the starting point for a more positive outcome.
Prevention & Early Action
The teen and young adult years are confusing, complicated and formative. Understanding what’s happening socially and developmentally — and how it can intersect with substance use — is fundamental to setting the stage for healthier outcomes.
Not sure how to prevent drug or alcohol use? Or what to do if you suspect or have discovered substance use? We have the science- and research-backed information to help you help your child.
How to spot signs of drug use
Shifts in mood & personality
- Sullen, withdrawn or depressed
- Less motivated
- Silent, uncommunicative
- Hostile, angry, uncooperative
- Deceitful or secretive
- Unable to focus
- A sudden loss of inhibitions
- Hyperactive or unusually elated
Behavioral changes
- Changed relationships with family members or friends
- Absenteeism or a loss of interest in school, work or other activities
- Avoids eye contact
- Locks doors
- Disappears for long periods of time
- Goes out often, frequently breaking curfew
- Secretive with the use of their phone
- Makes endless excuses
- Uses chewing gum or mints to cover up breath
- Often uses over-the-counter preparations to reduce eye reddening or nasal irritation
- Has cash flow problems
- Has become unusually clumsy: stumbling, lacking coordination, poor balance
- Has periods of sleeplessness or high energy, followed by long periods of “catch up” sleep
Hygiene & appearance
- Smell of smoke or other unusual smells on breath or on clothes
- Messier than usual appearance
- Poor hygiene
- Frequently red or flushed cheeks or face
- Burns or soot on fingers or lips
- Track marks on arms or legs (or long sleeves in warm weather to hide marks)
Physical health
- Frequent sickness
- Unusually tired and/or lethargic
- Unable to speak intelligibly, slurred speech or rapid-fire speech
- Nosebleeds and/or runny nose, not caused by allergies or a cold
- Sores, spots around mouth
- Sudden or dramatic weight loss or gain
- Skin abrasions/bruises
- Frequent perspiration
- Seizures and/or vomiting
How & where to look for signs of drug use
Use your nose.
Have a real, face-to-face conversation when child comes home after hanging out with friends. If there has been drinking or smoking, the smell will be on their breath, on clothing and in their hair.
Look them in the eyes.
Pay attention to their eyes, which will be red and heavy-lidded, with constricted pupils if they’ve used marijuana. Pupils will be dilated, and they may have difficulty focusing if they’ve been drinking. In addition, red, flushed color of the face and cheeks can also be a sign of drinking.
Watch their behavior.
How do they act after a night out with friends? Are they particularly loud and obnoxious, or laughing hysterically at nothing? Unusually clumsy to the point of stumbling into furniture and walls, tripping over their own feet and knocking things over? Sullen, withdrawn, and unusually tired and slack-eyed for the hour of night? Do they look queasy and stumble into the bathroom? These are all signs that they could have been drinking or using marijuana or other substances.
Search their spaces.
The limits you set with your child don’t stop at the front door or their bedroom door. If you have cause for concern, it’s important to find out what’s going on. Be prepared to explain your reasons for a search though, whether or not you tell them about it beforehand. You can let them know it’s out of concern for their health and safety. Common places to conceal vapes, alcohol, drugs or paraphernalia include:
- Inside drawers, beneath or between other items
- In small boxes or cases — think jewelry, makeup or pencil cases, or cases for earbuds
- Under a bed or other pieces of furniture
- In a plant, buried in the dirt
- In between or inside books
- Under a loose floor board
- Inside over-the-counter medicine containers (Tylenol, Advil, etc.)
- Inside empty candy bags such as M&Ms or Skittles
- In fake soda cans or other fake containers designed to conceal
Don’t overlook your teen’s cell phone or other digital devices. Do you recognize their frequent contacts? Do recent messages or social media posts hint at drug use or contradict what they’ve told you?
If your search turns up evidence of drug use, prepare for the conversation ahead and do not be deterred by the argument of invaded privacy. Stand by your decision to search and the limits you’ve set.
If you discover that your child is not likely to have been drinking or using other substances, this could be a good time to find out if there’s another explanation for any changes in their appearance or behavior that needs to be addressed.
Frequently asked questions about teen drug use
What’s the difference between teen experimentation and a real drug problem?
Experimentation usually means trying a substance once or a few times out of curiosity, often in a social setting, without major changes to a teen’s life. A problem is more likely when use becomes regular, when your teen seeks out substances on their own, or when you start seeing changes in school, friendships, mood, or health that last for weeks rather than days. The line isn’t always clear, and that uncertainty is normal — which is why noticing patterns matters more than reacting to a single incident. Learn more about how worried you should be →
My teen is moody and secretive. Is that drug use or just normal teenage behavior?
Some moodiness, secrecy, and pulling away from family is a typical part of adolescent development — teens are figuring out who they are and need privacy to do it. The signs that warrant a closer look are usually about cluster, duration, and intensity: several changes happening at once, lasting more than two weeks, or showing up alongside changes in friend groups, sleep, school performance, or appearance. Trust your gut. If something feels off, it’s worth a calm conversation. Read our guide to talking to your teen →
Should I drug test my teen?
Drug testing is a tool, not a solution, and it works best as part of a broader plan rather than a surprise move. At-home tests can produce false positives and false negatives, and using one without your teen’s knowledge can damage trust at exactly the moment you need it most. Before testing, it’s worth talking to your pediatrician or our helpline about whether testing is the right next step for your family — and if so, how to do it in a way that supports the relationship rather than fractures it.
What should I do if I find drugs or paraphernalia in my teen’s room?
First, take a breath before saying anything. A calm, prepared conversation almost always goes better than one driven by the shock of the moment. When you’re ready to talk, lead with care rather than punishment (“I’m worried about you” rather than “How could you do this?”), ask open-ended questions, and listen more than you speak. You don’t have to figure out the next step alone — our helpline can help you plan the conversation and decide what comes after.
How do I bring up drug use without damaging my relationship with my teen?
The relationship is your biggest protective factor, so protecting it is part of the work — not separate from it. Choose a low-pressure moment (a car ride or walk often works better than sitting them down), be specific about what you’ve noticed rather than making accusations, and make it clear you’re coming from a place of love and worry rather than anger. It’s okay if the first conversation doesn’t solve anything; opening the door matters more than getting it perfect. Get conversation tips and scripts →