Alcohol, other drugs and the brain

Alcohol and other drugs (AOD) can affect many parts of the body, including the brain.¹

But what happens to the brain when someone drinks alcohol or uses other drugs? 

Here, we look at how AOD affects the brain - including the impacts of long-term AOD use, and how the brain can recover. 

How do alcohol and other drugs affect the brain?

Alcohol and other drugs impact the brain by disrupting how it communicates.¹

Our brains use chemical messengers called ‘neurotransmitters’ to communicate. Neurotransmitters send signals throughout the body to manage how we think, feel, and move.¹

These neurotransmitters regulate things like mood, hunger, pain, attention, memory, sleep and movement.²

Some key neurotransmitters include:

• glutamate: speeds the brain up, and is critical in energy production
• GABA: slows the brain down - helping with relaxation and sleep
• dopamine: involved in regulating pleasure, reward, and motivation
• serotonin: regulates mood, appetite, and sleep
• noradrenaline: triggers alertness and stress responses.²

Drinking alcohol or using drugs interferes with these neurotransmitters, impacting how you think or feel.^{1, 3}

But the way AOD interacts with the brain varies a lot depending on the type of drug taken.^{1, 3}

For example, depressant drugs, such as alcohol, slow down the messages travelling between the brain and the body.¹

Alcohol does this by increasing GABA and dopamine, while reducing glutamate. This can make you feel more calm and relaxed, but can also cause trouble concentrating, slower reactions, and poor coordination.⁴

Stimulant drugs, like cocaine, speed up messages by increasing dopamine and noradrenaline.⁴ These changes can make you feel more energetic or confident, but also increase feelings of anxiety and irritability.⁵

The way different drugs interact with the brain plays a big part in the types of effects and harms they can cause.⁴

Drugs affect everyone differently

We know drugs affect everyone differently. Many other factors influence your experience, including your size, weight and health. 

And we know young people are more vulnerable, because their brains are still developing.⁶

For example, binge drinking during adolescence is linked with changes in the brain’s structure and function.^{6, 7} These brain changes are likely linked to poorer attention, memory, learning and decision-making abilities.^{6, 7}

To learn more about drug types and their effects visit our Drug Fact pages.

What happens in the brain if someone uses alcohol or other drugs regularly?

Most drugs affect the brain's reward system.⁴

This reward system teaches you to repeat behaviours important for survival, such as eating, drinking water, and connecting with others.

When you have a positive experience, your brain releases dopamine, creating pleasure so you'll remember and repeat it.^{1, 4}

Some drugs, such as opioids, activate this reward system by flooding your brain with dopamine. 

But with regular use over time, your brain lowers its dopamine activity to compensate for the overproduction.^{1, 4}

This signals that more of the drug is needed to feel the same initial effects – known as developing a ‘tolerance’.^{3, 4}

When this cycle begins, your body can become dependent on a drug to maintain the pleasurable effects and avoid any withdrawal symptoms or intense cravings when you stop using.³

People who experience AOD dependence often feel like they need it to go about their normal activities, or just to get through the day.

But most people who use AOD don't develop a dependence. While the way drugs affect the brain's reward system plays a big role, other factors also influence a person's risk of developing dependence – like genetics, environment and age.⁸

To find out more, visit our article on Understanding drug and alcohol addiction (dependence). 

How does alcohol and other drug dependence (addiction) change someone’s brain?

Frequent, long-term use of AOD can impact the brains’ structure and function.³

But the type and severity of impacts vary between each person, and can depend on:

• age – young people’s brains are particularly at risk, as they’re still developing
• type of drug/s used
• frequency, amount and duration of drug use
• physical and mental health.^{3, 9}

While we still need more research, we know different types of drugs are linked with changes in certain parts of the brain.

Alcohol 

Alcohol dependence is linked to structural changes in some parts of the brain, which can lead to difficulties with decision-making, attention, problem-solving, and memory.¹⁰ It also accelerates brain aging, and can increase the risk of dementia.¹¹

Cannabis

Frequent, long-term use of cannabis is associated with differences in the structure and function of regions of the brain involved with memory.¹²

Opioids

Opioid dependence is linked with changes affecting verbal working memory, impulsivity, decision making, and attention.¹³

Methamphetamine (ice)

Long-term methamphetamine use is linked with changes in the structure of several brain regions, particularly those involved in decision-making, regulating emotions, memory, motivation, and self-control.¹⁴ Methamphetamine dependence can also worsen mental health, and lead to anxiety, depression or psychosis.¹⁵

How does the brain recover after regular alcohol or other drug use?

Our brains have an incredible ability to adapt and repair, even after long-term AOD use or dependence.¹⁶

The brain continues to build cells and neural pathways throughout our life. It can adapt and change (called neuroplasticity) which allows it to modify, grow and reorganise itself.¹⁶

But it can take time for the brain to heal itself once someone stops using or significantly reduces their use of AOD. 

How long it takes depends on the type of drug used, and how much a person’s brain was affected.¹⁷

Some brain changes seem to improve soon after stopping use (abstinence) – especially within the first month.¹⁷ While others may not improve until after several months or longer.¹⁷ And in some cases, the impacts on the brain can be long-lasting or permanent.¹⁷

And some research suggests the brain’s structure can begin to recover before its function does – meaning the physical networks of the brain may be repaired, but only later do thinking, memory, and other abilities improve.¹⁷

There is still a lot we don’t know about brain recovery after prolonged AOD use. The pattern of recovery isn’t the same for everyone, and it doesn’t always happen in a straight line.¹⁷

What does the research tell us about brain recovery?

Research suggests that after someone with an alcohol dependence stops drinking:

• Improvements are seen for most brain functions within 6 to 12 months, including those related to attention, executive function, perception, and memory.¹⁰
• Other functions, such as processing speed and working memory, can recover even earlier.¹⁰

And a recent study also found that when young people stopped or reduced their binge drinking, structural improvements were visible in the brain, particularly in parts that are critical for decision-making, planning and impulsivity.¹⁸

When people with cannabis dependence stopped their use, parts of the brain involved in working memory and decision-making began recovering within weeks – though other areas were found to take months or longer.¹⁹

Studies on people who stopped using cocaine, heroin, or ketamine found signs of brain recovery, particularly in regions involved in self-control and decision-making.³

Longer periods of abstinence were linked with reduced cravings and stronger connections between brain regions involved in executive functioning – which refers to skills involved in managing everyday tasks, such as planning and problem solving.³

After about a month of abstinence from heroin use, it was found some structural brain changes returned to normal.¹³ And after 3 to 6 months of abstinence, executive function, information processing speed, and verbal and non-verbal learning all showed signs of recovery.¹³

For people experiencing a methamphetamine dependence, the picture is more complex.  But we know recovery is possible. A recent study found that men who stopped after long-term use showed structural improvements in areas of the brain linked to memory, executive function, and processing speed. Longer periods of abstinence were linked to improvements in verbal learning and memory.²⁰

How can we help the brain to recover after long term alcohol or other drug use?

For the brain to begin healing after an AOD dependence, drug use needs to be stopped or significantly reduced.¹⁷

But we know other activities can also support brain recovery, health and neuroplasticity. These include:

• Exercising regularly – this can increase the size of the hippocampus, a part of the brain vulnerable to AOD use, and can help improve metal health. 
• Practicing mindfulness – activities like breathing techniques or meditation can help strengthen brain circuits damaged by AOD use
• Eating a balanced and nutritious diet – helps make sure the brain has the right vitamins and minerals it needs. 
• Getting enough sleep – the brain flushes out toxins during sleep, and good quality sleep can help support brain recovery
• Connecting with others – building supportive, non‑judgemental social connections can release oxytocin and regulate dopamine in the brain, helping to repair neural pathways and improve recovery outcomes.²¹

Free and low-cost help and support services are also available to help you cut back or stop your use – see a list of services available below. 

Help and support

If you’re experiencing an AOD dependence, concerned about your use of AOD, or worried about someone else, there is help and support available:

• Call the National Alcohol and Other Drug Hotline on 1800 250 015 for free and confidential advice, information and counselling about alcohol and other drugs.
• Use the confidential Path2Help portal to get matched with information and services specific to your needs.
• Search our Help and Support directory to find your preferred support, by adding your location or postcode and filtering by service type.  
• Online support and resources are also available, including:
• Counselling online: a confidential online service staffed by professional counsellors with qualifications and experience in alcohol and drug counselling and treatment. 
• SMART Recovery Australia: an evidence-based recovery method that supports people with substance dependencies.