Recognising Substance Use in Teenagers: A Guide for Parents and Carers

The Reality of Teenage Substance Use

Substance use among teenagers is more common than most parents want to believe. Surveys across many countries find that by the age of 17, a significant majority of young people have tried alcohol, and substantial minorities have tried cannabis, nicotine products, or other substances. This does not mean that all, or even most, teenage experimentation leads to harm. For many teenagers, limited experimentation with alcohol, for example, is part of normal adolescent risk-taking that does not progress to problematic use.

However, teenage substance use does carry real risks that differ from adult use. The adolescent brain is still developing, and exposure to substances during this period can affect neurological development in ways that increase the risk of addiction and mental health difficulties. Some substances are particularly harmful to developing brains. And the social and legal contexts in which teenagers use substances, often in unsupervised settings, increase the risk of accidents, violence, and exploitation.

Understanding what to look for, how to respond, and when to seek professional help are important tools for any parent.

Why Teenagers Use Substances

Understanding the reasons teenagers use substances helps parents respond more effectively than assuming it is simply rebellion or bad decision-making.

Common reasons include: peer influence and the desire to fit in; curiosity and risk-taking, which are developmentally normal in adolescence; escapism from stress, anxiety, depression, or difficult home circumstances; pleasure-seeking in a period of heightened reward-sensitivity; and normalisation through family patterns of substance use.

Teenagers who are struggling with mental health difficulties, social isolation, or difficult life circumstances are at higher risk of developing problematic substance use rather than simply experimenting. Addressing underlying difficulties is often as important as addressing the substance use itself.

Signs of Alcohol Use

Alcohol is the most commonly used substance among teenagers worldwide. Signs that a teenager may be drinking regularly include:

• Smell of alcohol on breath or clothing, sometimes masked by mints or perfume
• Coming home later than agreed, appearing unsteady, slurring words, or unusually boisterous
• Unexplained gaps in memory of evenings or events
• Finding alcohol hidden in bedrooms or bags
• Significant changes in friend group toward older teenagers or young adults
• Frequently attending events or gatherings where alcohol is likely to be present
• Spending more money than can be accounted for by known allowance or earnings

Signs of Cannabis Use

Cannabis is the most commonly used illegal drug among teenagers in many countries. Signs include:

• Distinctive sweet, skunky smell on clothes, hair, or breath
• Red or bloodshot eyes, particularly after being out
• Increased appetite, especially for sweet or salty foods, following outings
• Periods of appearing very relaxed, slow, or detached alternating with apparent normality
• Finding paraphernalia: rolling papers, small pipes, lighters, small bags of dried plant material
• Motivation changes: withdrawal from previously enjoyed activities, declining academic performance
• Increased paranoia or anxiety, particularly in heavy users

Signs of Nicotine and Vaping

Vaping has become extremely common among teenagers. Signs include:

• A sweet or fruity smell on breath or in rooms (different from tobacco smoke smell)
• Finding disposable vapes, vape devices, or pods
• Increased thirst and dry mouth (a common side effect of vaping)
• Unexplained coughing or throat irritation
• Nicotine withdrawal symptoms between outings: irritability, difficulty concentrating

Signs of Other Drug Use

Signs of use of other substances, including MDMA, cocaine, ketamine, or prescription medications misused recreationally, can include:

• Dramatic mood swings over short time periods
• Dilated or constricted pupils in contexts where lighting would not explain this
• Unusual sweating, clenching of jaw, or grinding teeth
• Nosebleeds (associated with cocaine or other snorted substances)
• Unexplained euphoria or energy followed by significant crashes
• Finding unexplained pills, powders, or capsules
• Significant, unexplained weight loss

General Behavioural Changes

Beyond substance-specific signs, the following general changes warrant attention, particularly in combination:

• Significant withdrawal from family life or previous friendships
• Unexplained changes in sleeping patterns, particularly sleeping through the day
• Declining school performance and attendance
• Increased secrecy around phone, whereabouts, and activities
• Unexplained need for money, or money going missing from the household
• Drastic changes in friend group, particularly toward older individuals with no visible connection to school or community

How to Respond

The quality of parental response to suspected or confirmed substance use has a significant impact on outcomes. Responses that shut down communication make the problem worse. More effective approaches include:

Stay calm. A calm, non-panicked response is far more likely to keep dialogue open than an immediate confrontation. If you discover evidence of substance use when your teenager is not present, give yourself time to process your reaction before having the conversation.

Express concern, not just anger. Framing the conversation around worry for the teenager's health and safety, rather than rules and punishment, is more likely to be heard.

Listen before speaking. Ask open questions. What is going on? How are you feeling lately? What is happening with your friends? Understanding the context, the reasons, and the extent of use gives you much better information to work with than accusation does.

Be honest about risks without catastrophising. Teenagers respond to accurate information better than to exaggerated warnings they have reason to disbelieve. The real risks of substance use, particularly to developing brains and in terms of impaired decision-making, are serious and worth communicating clearly without hyperbole.

Do not rely solely on punishment. Punishing substance use without understanding or addressing why it is happening often drives it underground without reducing it. Rules and consequences are part of the picture, but so is support for underlying difficulties.

When to Seek Professional Help

Professional support should be sought when:

• Substance use appears to be regular and entrenched rather than experimental
• Substance use is clearly connected to or worsening mental health difficulties
• Your teenager cannot or will not stop despite serious consequences
• There are physical health effects from use
• The situation is beyond what the family can manage alone

Starting with a GP or family doctor is appropriate. Many areas also have specialist young people's drug and alcohol services. These are typically supportive and non-punitive in approach, recognising that effective support for young people with substance problems requires engagement rather than coercion.

Conclusion

Teenage substance use is a real and common challenge that most families navigate without catastrophe, particularly when parents respond with calm, informed engagement rather than panic or denial. Knowing the signs, responding in ways that keep communication open, and seeking professional support when needed are the most important tools available. You do not have to manage this alone.