You Know Something Is Off. Trust That Instinct.
Parents have an uncanny ability to sense when their teenager is hiding something. Maybe it’s a gut feeling. Maybe it’s a specific change you can’t quite articulate. Either way, if you’re reading this, something prompted the search — and parental instinct is right more often than not.
About 15% of high school seniors report using illicit drugs in the past month. Nearly 30% report past-month alcohol use. Vaping adds another layer — 10% of 12th graders vaped nicotine in the past month as of 2023 data. The numbers mean that teen substance use isn’t rare, and recognizing it early makes an enormous difference in outcomes.
Behavioral Warning Signs
Sudden academic decline. Grades dropping, missing assignments, skipping classes. One bad semester can happen for many reasons, but a sharp unexplained decline — especially paired with other signs on this list — deserves investigation.
New friend group, especially secretive about it. Teens naturally evolve friendships. But if your previously open kid suddenly has friends you’ve never met, won’t bring home, and gets evasive when you ask about them, that’s a flag.
Money issues. Asking for money more often with vague explanations. Money missing from your wallet or purse. Selling personal belongings. Substances cost money, and teens have limited income.
Extreme mood swings. Yes, mood swings are part of normal adolescence. But substance-related mood changes tend to be more extreme and less tied to identifiable triggers. Watch for irritability that seems disproportionate, euphoria that comes out of nowhere, or emotional flatness.
Loss of interest in activities they used to love. Quitting the soccer team, dropping out of band, abandoning longtime hobbies. When substance use fills the reward center, other activities feel less appealing.
Increased secrecy and defensiveness. Locking their phone, locking their door, rage when you ask questions. Some privacy seeking is developmentally normal. Aggressive defensiveness about whereabouts and activities goes beyond normal.
Physical Signs
- Bloodshot or glazed eyes (marijuana, alcohol)
- Pupils unusually dilated or constricted (stimulants, opioids)
- Sudden weight loss or gain
- Deteriorating hygiene and appearance
- Unusual smells on breath, clothing, or in their room (marijuana, alcohol, vape)
- Unexplained nosebleeds (snorting substances)
- Track marks or unexplained bruises (less common but serious)
- Persistent cough or respiratory issues (vaping, smoking)
- Coordination problems, slurred speech (when sober)
Digital Red Flags
If you have access to your teen’s device (and the ethical debate around teen privacy is real), watch for:
- Conversations referencing drug slang or code words (which change constantly — current teens use terms you won’t recognize)
- Cash transfer apps like Venmo or Cash App with frequent small transactions to people you don’t know
- Social media posts showing parties, substance use, or coded references
- Deleted message history (consistent deletion of texts or chats)
How to Approach the Conversation
This is where most parents stumble. The instinct is to confront, accuse, and ground for life. But research consistently shows that approach backfires. Here’s what works better:
- Pick the right time. Not during an argument. Not when they’re walking out the door. Choose a calm, private moment when neither of you is stressed.
- Lead with concern, not accusation. “I’ve noticed some changes and I’m worried about you” lands differently than “Are you doing drugs?”
- Ask open-ended questions. “How are things going with your friends?” opens more doors than “Who were you with last night?”
- Listen more than you talk. Your teen is more likely to share if they feel heard rather than interrogated.
- Stay calm if they admit to use. Your reaction in this moment determines whether the conversation continues or shuts down permanently. You can express concern and set boundaries without losing your composure.
- Avoid ultimatums you can’t enforce. “If I ever catch you drinking again, I’m sending you to military school” destroys credibility if you can’t follow through.
When Normal Teen Behavior Crosses Into Concern
Let’s be realistic: some signs on this list overlap with normal adolescent development. Teens naturally seek more privacy, push boundaries, try on different identities, and have mood swings. The distinction often lies in patterns and clustering:
- One or two signs in isolation: probably normal development. Monitor but don’t panic.
- Three or more signs clustering together: legitimate concern. Have the conversation.
- Physical signs (bloodshot eyes, smell, paraphernalia found): clear evidence requiring immediate action.
Frequently Asked Questions
Should I drug test my teen?
This is genuinely complicated. Some addiction specialists support it as a tool (it gives teens an “out” with peers: “I can’t, my parents test me”). Others argue it damages trust and teens find workarounds anyway. If you choose to test, frame it as a safety measure, not a punishment. And know that home tests have significant false-positive and false-negative rates.
What if my teen is using marijuana and says it’s “just weed”?
Adolescent brains are still developing until age 25, and cannabis use before 25 has documented effects on brain development, particularly areas involved in memory, learning, and executive function. “Just weed” isn’t harmless for a developing brain, even if the risks are lower than alcohol or opioids. Have this conversation with facts, not fear-mongering.
When does teen experimentation become a serious problem?
Red lines include: using substances alone, using to cope with emotions, increasing frequency and quantity over time, continuing despite consequences (academic, legal, relationship), and any involvement with highly addictive substances (opioids, methamphetamine). The CRAFFT screening tool helps formalize this assessment.
