Signs Your Teen May Be Using Drugs or Alcohol, and What They Can Also Mean

The most reliable signs that a teen may be using drugs or alcohol are clusters of change rather than any single clue: new friends your teen won't introduce, grades that slide, a sport or hobby that suddenly doesn't matter, more secrecy, and physical or household clues that don't have another explanation. Almost every one of those signs can also come from a normal hard stretch of adolescence, or from anxiety or depression, which is why the goal is to notice patterns calmly and ask questions rather than build a case.

Most parents who search this are frightened, and many feel guilty for not noticing sooner. Both feelings make sense, though neither one is a reason to wait or to panic, and our guide to teen substance use gathers the next steps in one place.

How common is drug and alcohol use among teens?

Drug and alcohol use is less common among teens than most parents fear, and it rises steadily through high school. The National Institute on Drug Abuse (NIDA) reported results from the 2025 Monitoring the Future survey, collected from 23,726 students in 270 schools between February and June 2025 (NIDA, 2025). The share of students who reported no marijuana, alcohol, or nicotine use in the past 30 days was 91% of 8th graders, 82% of 10th graders, and 66% of 12th graders.

Use in the past year looked like this in the same survey:

Those numbers cut both ways. Your teen is probably not using, and a calm, curious approach fits the odds, while the jump between 8th and 12th grade means the conversations matter more every year, which is what our guide on how to talk to your teen about substances is for.

What are the behavioral signs a teen may be using?

Behavioral changes are usually the first signs parents notice, and they tend to show up at school, with friends, and at home before anything physical does. NIDA lists signs that can point to a problem with drugs, including hanging out with different friends than usual, not caring about appearance, getting lower grades, missing classes or skipping school, losing interest in favorite activities, getting in trouble at school or with the law, different eating or sleeping habits, and more problems with family and friends (NIDA, 2021).

SAMHSA's Talk. They Hear You. campaign adds mood changes like flare-ups of temper, irritability, and defensiveness, rebellion against family rules, and a reluctance to let you get to know new friends (SAMHSA, 2024). Other changes parents often describe include:

• New secrecy about the phone, a locked bedroom door, or plans that keep changing.
• Money going missing, or your teen always seeming to need more of it.
• Dropping a sport, club, or job they used to care about, without a clear reason.
• Stories about where they were that don't add up when you check.

Any one of these is ordinary teenage behavior on its own. Several of them arriving in the same season, along with a teen who seems to be pulling away from the people who used to know them best, is what's worth paying attention to.

What are the physical and environmental signs?

Physical signs of substance use can include bloodshot eyes, memory lapses, poor concentration, lack of coordination, slurred speech, and the smell of alcohol on the breath, according to SAMHSA's list of warning signs for underage drinking (SAMHSA, 2024).

Environmental signs are the things you find rather than the things you see in your teen. Examples include alcohol missing from the house, prescription medication that runs out faster than it should, vape devices or chargers that don't belong to a phone, lighters or rolling papers, eye drops or air fresheners that weren't there before, or pills you don't recognize. Vapes in particular can look like ordinary objects, and the Centers for Disease Control and Prevention (CDC) notes that they come in several forms, including disposable devices, prefilled or refillable pods and cartridges, and larger tank systems (CDC, 2024).

If you've already found something, our guide on what to do if you find drugs or vapes walks through the next few hours. If what you found includes pills that didn't come from a pharmacy, read what to tell your teen about fentanyl and counterfeit pills before you do anything else, because a pill that looks like a real prescription may not be one.

How can parents tell substance use from normal teen behavior or mental health issues?

Parents usually can't tell substance use apart from normal adolescence or a mental health issue from the signs alone, because the lists overlap almost completely. SAMHSA says it directly: some warning signs "also reflect normal growing pains," and a problem is more likely if you notice several signs at the same time, if they occur suddenly, or if some are extreme (SAMHSA, 2024).

Withdrawal, irritability, falling grades, and changes in sleep are also common signs of depression and anxiety, which our guide to the signs of depression in teens covers. Substance use and mental health often travel together too, sometimes because a teen is using to cope with feelings they can't name. Our page on when substance use and mental health overlap goes further, and the table below compares how the same change can look depending on what sits underneath it.

Whatever the cause turns out to be, the response at the start is similar: stay close, ask what's going on, and bring in a professional who can look at the whole picture. You don't need to know whether it's drugs, depression, or both before you ask for help.

Why does it matter to notice early?

Noticing early matters because a teen's brain is still developing, and substances affect it in ways they don't affect an adult's. CDC notes that nicotine "can harm the parts of an adolescent's brain that control attention, learning, mood, and impulse control" (CDC, 2024). Early conversations also tend to go better than late ones, because a teen who has been experimenting for a few weeks has less invested in hiding it than one who has been using for a year.

Noticing early doesn't mean searching your teen's room every night or reading every message. In my experience the parents who pick up on changes are usually the ones who are simply around, who drive the carpool, know the friends' names, and are awake when their teen gets home.

When should parents get professional help?

Parents should get professional help when a pattern of changes has held for a few weeks and is affecting school, family life, or your teen's health, even if you're not sure substances are involved. This guide can help you notice patterns, but only a licensed professional can evaluate your teen. A pediatrician or family doctor is a good first call, since they can screen for substance use, check for physical causes, and refer you to a therapist or counselor who works with teens.

SAMHSA suggests also talking with people you know and trust, such as your child's school counselor, other family members, or your doctor, and checking with your health insurer or your employer's employee assistance program for referrals (SAMHSA, 2024). If a therapist recommends more than weekly sessions, our guide on how to know what level of care your teen needs explains the options.

Some situations call for acting right away rather than watching:

• Call 911 if your teen can't be woken, is breathing slowly or with difficulty, or has discolored lips or fingernails, which CDC lists among the signs of an opioid overdose (CDC, 2024).
• Call or text 988 (the Suicide & Crisis Lifeline), or call 911 if your teen is in immediate danger, if your teen talks about hurting themselves or not wanting to be alive. Our page on crisis options for parents covers what happens when you call.
• Call your pediatrician the same day if you find pills you can't identify, your teen has been drinking heavily or blacking out, or your teen has been driving after using.

This article shares practical guidance for parents and is not medical advice. We're not clinicians or doctors. If your teen is struggling, contact a licensed mental health professional or your teen's doctor, and if you have a serious concern about their safety, call 911 or call or text 988. Editorial standards