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Cannabis can harm your developing brain.

If you’re under 25, weed can impact your brain – affecting memory, learning and mental health.

Reduce your riskof harm

The earlier you start and the more you use,

the greater the risk of harm.

How does cannabis harm the developing brain?

The active ingredient in cannabis binds to receptors in the brain. This can impact the important development it goes through between the ages of 14 and 24. 

Memory and learning

Cannabis can reduce the ability to focus, pay attention, be organised, and make decisions. Less information gets saved as memories, which can make it harder to learn and remember new things.

Mental health

Cannabis use may be associated with low mood, anxiety, and depression. Regular and heavy use increases the risk of developing mental health issues, including psychosis and dependence. 

The earlier you start using cannabis and the more frequently you use it, the greater the risk of developing dependence and long-term problems with learning, memory, and mood. 

Side effects

What is cannabis?

A person’s brain chemistry, genetics, and life experience can determine how they experience the drug.

Cannabis comes from a plant called cannabis sativa. Other names include weed, pot, hash, dope, gunja, bud, joint, marijuana. 

Cannabis can:

  • Change your mood, it may make you feel very relaxed and sleepy or even laugh a lot
  • Increase heart rate, and cause headaches, dizziness and nausea
  • Impair memory, balance and coordination
  • Cause difficulties thinking and problem solving
  • Cause some people to get paranoid (fearful and suspicious), worried or restless

Cannabis contains two main active compounds:

  • THC (delta-9 tetrahydrocannabinol)
  • CBD (cannabidiol)

THC is the psychoactive chemical that affects the way you think, feel and behave. CBD has no psychoactive effects.

Cannabis comes in different forms and can be smoked, eaten or vaporised. Consumption of the cannabis flower/buds are the most common form.

Depending on how much is used and the method of use (e.g. smoking or eating), effects can be felt for up to 6 to 12 hours.

Did you know?

Young people who start using cannabis at an early age may be more likely to:

Drop out of high school

Become dependent on


Use other drugs

Experience mental health issues, self-harm and suicide

Tips to reduce your risk of harm

The most effective way to reduce the risk of harm is to not use cannabis. If you do choose to use cannabis, it’s important to know ways to reduce the risk of harm.

It’s best to delay using cannabis for as long as possible while the brain is still developing.

Try a small amount first

Take breaks from using

Use less or no tobacco

Always try a small amount first to feel the effects before using more, as every product will be different.

Using cannabis more often and in large amounts, can affect your physical and mental health. Take breaks from using when you can.

Mixing tobacco with cannabis increases the risk of nicotine dependence and smoking related cancers. Try to reduce or not use tobacco in your mix.

Avoid alcohol or other drugs

Don’t use cannabis and drive

Look out for your mates

Mixing alcohol and other drugs with cannabis can cause increased and unwanted effects. Try to use cannabis without other drugs or use less of each if you use together.

Cannabis affects your driving ability, attention and reaction time. It's against the law to drive with cannabis in your system. Cannabis can still be detected when the effects wear off.

If your friend experiences unwanted effects, try to keep them calm. Never leave them alone and get help if necessary.

Try to avoid deep inhales

Try to use lower THC

Avoid synthetics

High THC can increase the risk of experiencing mental health issues and dependence. Try to use cannabis with lower THC and take breaks from using when you can.

Try to avoid deep inhales or holding your breath when smoking. You will still experience the effects but will reduce some of the toxins in your lungs.

Synthetic cannabinoids do not have the same effects as cannabis. They are strong psychoactive drugs which can cause physical and mental health harms, including death.

Cannabis and harm later in life

Regular cannabis use over the long term is associated with respiratory problems, heart disease and cancers. 

If you have personal or family history of mental health issues or lung or heart conditions, you are at greater risk of harm. Avoiding using cannabis is the safest way to look after yourself.

If you are using cannabis and want to reduce or stop using, you can talk to an Alcohol or Other Drug worker, GP, or counsellor who can provide support and steps to check out your general and mental health. 

For more information

About the health effects and risks of cannabis, 

visit the Drug Aware website.

Acknowledgement of Country

Alcohol and Drug support line (24/7)

We wish to acknowledge the traditional custodians throughout Western Australia and their continuing connection to the land, waters and community. We pay our respects to all members of the Aboriginal communities and their cultures, and to Elders both past and present.

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A free 24-hour, state-wide confidential, non-judgemental telephone counselling, information and referral service for anyone seeking help for their own or another person’s alcohol or drug use.

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