Key points
- A drug is any chemical or substance that changes how the body works. This includes prescription medicines, caffeine, alcohol, tobacco and illegal drugs.
- Drinking alcohol can change the way the brain develops.
- It is not legal or recommended for people under age 18 to drink alcohol.
- Drugs can affect a teen’s mood, energy, thinking, coordination and their view of the world.
- If you are worried that your teen may be addicted to alcohol or drugs, there are many ways to support them.
- In a drug or alcohol emergency, such as a drug overdose, call an ambulance (000) immediately.
Alcohol
What is alcohol?
The word ‘alcohol’ usually refers to alcoholic drinks, such as beer, wine, or spirits like vodka. These drinks contain a chemical substance called ethanol that affects the brain. Every alcoholic drink contains different amounts of ethanol; that is why
some are stronger than others. The more ethanol, the more alcoholic the drink.
Harm from alcohol is related to how much a person drinks: drinking less means a lower risk of harm.
In Australia, it is not legal or recommended to drink alcohol under the age of 18.
How does alcohol affect the body?
The ethanol in alcoholic drinks is a 'depressant.’ It slows down brain activity and the messages sent between the brain and body.
- In small doses, alcohol can make a person feel relaxed and less inhibited.
- In larger doses, alcohol can make a person drowsy, slower to respond and affect their coordination.
- In very large doses, ethanol is dangerous. It can be toxic and cause alcohol poisoning, leading to vomiting, loss of consciousness and even death.
Is alcohol bad for teens?
Teen brains change every day. Research shows that regular, heavy alcohol drinking can cause changes in the brain – especially in key areas like learning, memory and decision-making. Starting to drink alcohol at a younger age also makes people more likely
to become addicted to alcohol.
In the long term, drinking large amounts of alcohol may:
- permanently damage organs like the liver, brain and heart
- increase the risk of at least seven types of cancer
- lead to ongoing mental health challenges like depression.
Binge drinking
Teens are more likely to drink a lot of alcohol in one night. This is called ‘binge drinking.’ Binge drinking is having four or more standard drinks for women, or five or more standard drinks
for men, within two hours.
Binge drinking is linked with a higher risk of mental health challenges, taking risks, car accidents, and using other drugs. Research shows that binge drinking can be as harmful as daily drinking.
Drugs
What is a drug?
A drug is any chemical or substance that changes how the body works. The word ‘drugs’ often refers to illegal or recreational substances. However, medicines a doctor or nurse prescribes are also drugs.
The most common types of drugs are:
- Medicines for sale in supermarkets or pharmacies, such as paracetamol
- Prescription medicines used for medical reasons, such as antibiotics to treat infections
- Prescription medicines used for non-medical’ reasons, such as taking strong pain medicine without any pain
- Substances such as caffeine, alcohol and nicotine
- Illegal drugs like marijuana (weed), cocaine and ecstasy.
Some drugs are taken by mouth, like tablets or liquids, while others are inhaled or injected using a needle.
How do drugs affect the body?
When a person takes drugs, the substances enter their bloodstream and impact different parts of the body. Most drug effects happen when they reach the brain.
In the brain, drugs can change a person’s:
- mood
- energy levels
- thought processes
- coordination and speech
- perception of reality (for example, hallucinating and seeing things that seem real but are not).
Certain drugs have after-effects when they wear off. People may feel depressed or very tired; this is sometimes called a ‘come down.’
Types of drugs
Drugs are usually grouped based on how they change the body. The most common categories are:
- Depressants, which slow down brain activity. For example, alcohol, ketamine and opioids (like heroin).
- Hallucinogens, which change perception (sense of reality). For example, magic mushrooms (psilocybin) and LSD (lysergic acid diethylamide).
- Stimulants, which speed up brain activity. For example, caffeine, nicotine and ecstasy.
Some drugs fall into more than one category. For example, marijuana (weed) is a depressant and a hallucinogen.
Illegal drugs are not regulated like legal ones. There is no standard oversight process, so it is almost impossible to know which ingredients illegal drugs contain. People may also mix drugs with other substances to create more product and increase their
profits. This creates new risks; people might accidentally overdose or take something they did not want.
Prescription drugs
Some people misuse legal drugs (medicines) that doctors prescribe.
This could mean taking:
- a higher dose than what a doctor prescribed
- medicine more often than a doctor prescribed
- someone else's medicine.
Some examples of prescription drugs that people might misuse include:
The misuse of prescription medicines is increasing.
Risks of taking drugs for teens
Every drug affects the body differently, but many have the same risks in common for teens.
- Certain drugs can be dangerous – especially if your teen overdoses. Overdosing can lead to sickness, heart or breathing problems, and even death.
- Just like alcohol, drugs can permanently change a teen's brain. Parts of the brain responsible for key functions like memory and decision-making may never form properly.
- Most drugs can influence behaviour in some way. For example, they may make your teen feel angry or more likely to take risks.
- Drugs can be addictive. Over time, your teen may get used to having drugs in their system and find it hard to function without them.
- Some drugs have many names. These so-called ‘street’ or slang names make it hard for your teen to know what they are taking.
- If your teen spends a lot of time taking drugs, they may act or feel different. This can cause problems with their school or work, money and relationships.
Helping your teen to stay safe
As a parent and caregiver, you have a vital role in protecting your teen from the harms of alcohol and drugs.
Modelling good behaviours is one of the best ways to teach your teen. Avoid drinking large amounts of alcohol where there may be children nearby. When you are taking care of children, you should be able to make clear decisions and respond in an emergency;
therefore, it is important not to be intoxicated at these times.
In Australia, the legal driving blood alcohol limit for full licence holders is 0.05% blood alcohol concentration (BAC). Do not drink and drive if you think you may be above the limit. It is illegal to drive with any drugs in your system.
You should never take illegal drugs around children.
Supplying alcohol to your teen has been linked to alcohol-related harm and binge drinking. Always keep alcohol and drugs (including medicines) locked away and out of reach of children.
Have open conversations with your teen about how they can stay safe around alcohol and drugs – for example, at parties and out with friends. You could suggest ways to respond if someone offers them alcohol or drugs, how to say no, and who they can call
if they feel unsafe.
Signs of drug and alcohol dependence
Alcohol and drug addiction is also known as ‘dependence.’ It can include both physical and emotional symptoms.
Signs of possible alcohol or drug dependence in teens are:
- Withdrawing from family and/or friends
- Skipping usual activities like sports
- A sudden drop in school marks
- Taking multiple days off school
- Asking for money frequently
- Spending extended time away from the house without explaining where they are
- Acting jumpy or irritable
- Physical symptoms such as vomiting, sweating and shaking.
Helping your teen with drug and alcohol use
In a drug or alcohol emergency, call an ambulance (000) immediately.
The best thing you can do to support your teen through alcohol and drug use is to build a strong relationship with them. This will teach your teen that they can come to you for judgment-free advice and support. Even if you are frustrated, try not to shame
your teen – this may only push them away.
For professional support, your teen can speak with their doctor. They can recommend an alcohol and other drug service for young people or a mental health professional who specialises in addiction.
If your teen wants support from someone online or via phone, they can contact the National Alcohol and Other Drug Hotline or headspace.
In Victoria, they can also connect with the Youth Drug and Alcohol Service (YoDAA).
Common questions about drugs and alcohol
What is a standard drink?
In Australia, a standard drink always contains 10g (grams) of pure alcohol. What changes between drinks is the alcohol content. For example, one standard
drink is approximately 100mL (millilitres) of red wine (13.5% alcohol) but only 30mL of spirits (40% alcohol).
Why do teens drink or take drugs?
Risks are a way for teens to learn from their experiences and form their own identities in the world. It is normal for teens to take risks. However,
some risks can be problematic for teens, including drinking alcohol and taking drugs.
There are lots of reasons why teens may drink or take drugs. These substances may make them feel more relaxed, happier, comfortable or less anxious in social situations. Sometimes young people drink or take drugs to experiment or try to fit in
with their friends.
Are all drugs bad?
As simple medicines like paracetamol are types of drugs, it is not correct to say all drugs are bad. Many drugs have positive effects on the body, like helping with pain or healing infections, as long as they are taken as directed.
How does the government decide which drugs are illegal?
The government of each country decides which drugs are illegal. Most drugs are illegal because they do not have medical benefits, or they are addictive, harmful and/or dangerous – especially in large doses.
Are all legal drugs safe?
Drugs are not automatically safe if they are legal. In most cases, a drug's safety depends on the amount taken. For instance, people can get very sick from taking too much paracetamol, even though it is available at the supermarket without a prescription.
How do I teach my teen to say no to drugs or alcohol at a party?
I It can be hard for a teen to say no when their peers are using drugs or drinking alcohol. Try encouraging your teen to be assertive and confident in these situations. For example, saying 'No thanks' or 'I prefer not to' is enough. If they feel
more comfortable giving an excuse, they could say they have work or sports training the next day. The most important thing to convey to your teen is that they always have the right to say no. Sometimes, it may be best for them to leave the
party or spend time with other friends.
How can I teach my teen to stay safe around alcohol?
If your teen is going to parties where there may be alcohol, or their friends are drinking, you should teach them how to reduce their risk. Encourage your teen to stay around people they trust, and make sure they have a way to contact you or another
adult if they feel unsafe. They should also plan how they will get home before they go out at night.
Teach your teen to avoid mixing alcohol and other drugs. If they take prescription medicines, they should check if it is safe to drink alcohol while on them. Finally, make sure your teen knows to drink plenty of water and eat regularly – especially
if they are out for a long time.
Is it true that most teens are drinking alcohol and using drugs?
Most teens in Australia are choosing not to drink or use other drugs. A recent Australia-wide survey of high school students
showed that most teens said they had never smoked, vaped or used drugs. More than one in three teens surveyed said they had never drunk alcohol in their lifetime.
For more information
Developed by The Royal Children’s Hospital Adolescent Medicine (RCH) department, with input from the Psychology department. We acknowledge the input of RCH consumers and carers.
Reviewed August 2025
Please always seek the most recent advice from a registered and practising clinician.