Alcohol and the brain

Every time you drink alcohol, it affects your brain. As well as feeling less inhibited and being less able to make clear judgments, you are risking long-term effects for your brain and mental health. 

How alcohol affects your brain

The type of alcohol in alcoholic drinks is a chemical called ethanol. Ethanol is a very small molecule, so when you drink it reaches most parts of your body – including your brain.

Small amounts of alcohol can cause initial feelings of relaxation, but what’s actually happening is that alcohol is suppressing activity in parts of the brain associated with inhibition.¹

Even after you’ve stopped drinking, your brain and central nervous system are still affected while they process the alcohol, which can lead to withdrawal symptoms. Severe withdrawal symptoms are life-threatening – find out more about what they are and how to get help here.

Brain chemistry

The way alcohol affects the brain is partly down to its effect on ‘neurotransmitters’ - the chemicals that help to transmit signals from one nerve (or neuron) in the brain to another. The more you drink in a session the higher the chance it will cause feelings of tension and anxiety, because of effects on these brain chemicals.²

Research has found that regular heavy alcohol consumption over a long period is associated with a decline in the number of brain cells (or ‘neurons’), and their quality.³

Regular heavy drinking can cause:

• Withdrawal symptoms- as your brain and central nervous system process the alcohol, the brain has had to adjust to regularly dealing with alcohol. If alcohol is suddenly not there, you can suffer from ‘rebound agitation’ where the adjustment causes feelings of intense anxiety and irritability.
• Alcohol dependence- where you become psychologically and/ or physically addicted to drinking.

A good way to protect your brain health is to follow the UK Chief Medical Officers’ low risk drinking guidelines. To keep health risks from alcohol to a low level, it’s safest to drink no more than 14 units a week - spread over three or more days with several drink-free days every week, and no bingeing.

Alcohol-related brain damage

Alcohol-related brain damage (ARBD) is damage caused to the brain by regular heavy drinking or binge drinking over several years.⁴ (It’s also sometimes called ‘alcohol-related brain injury’.)

Alcohol-related brain damage can happen for a number of reasons:

• Alcohol is toxic. When alcohol molecules reach the brain, they can damage brain cells
• Brain cells can be damaged if your body doesn’t have enough water – and alcohol is dehydrating (a ‘diuretic’)
• Higher blood pressure caused by alcohol is linked to stroke (where the brain is injured by being starved of oxygen)
• Liver damage caused by alcohol (or other causes) can mean the brain is exposed to more toxins which would normally be dealt with by the liver (‘hepatic encephalopathy’)
• Fights and falls linked to drinking alcohol can cause brain injury
• Heavy drinking tends to be associated with poor diet, which can cause malnutrition and can be harmful for the brain
• The brain doesn’t get enough essential vitamins (especially B vitamins, like thiamine) because alcohol interferes with their absorption from your diet

Heavy drinking can lead to malnutrition (due to poor appetite or poor nutrition, or diarrhoea and vomiting) which can make the brain suddenly short of the vital vitamin B1 – also known as thiamine. This, in turn, can cause a specific brain illness called Wernicke-Korsakoff Syndrome, leading to impaired recent memory, difficulty learning new information and poor balance.⁵

Alcohol-related brain injury can also cause alcohol-related dementia. In common with many other health harms caused by alcohol, the likelihood of developing these problems increases the more you drink over time.

Find out more about alcohol and dementia

Binge drinking and blackouts

Drinking a lot of alcohol in a short space of time (which some people call binge drinking, or heavy session drinking) can be dangerous. It affects your brain function – making you more impulsive, slowing your reaction times and affecting your balance.⁶

You are more likely to vomit, have an accident or become involved in a fight, or even lose consciousness with the risk that breathing stops.⁷

Another possible consequence is ‘blackouts’ - gaps in your memory for events that occurred while you were intoxicated. These gaps happen if you drink enough alcohol to temporarily block the transfer of memories from short-term to long-term storage - known as memory consolidation.⁸ 

Find out more about the dangers of binge drinking

Alcohol and brain development

The developing brain can be harmed by alcohol.

Alcohol can cause harm to a developing baby at any point during pregnancy,⁹ and the more that is consumed, the greater the risk.^10,11

When a pregnant woman drinks, alcohol goes through the placenta to the fetus via the bloodstream. This has a number of harmful effects on a developing fetus, including destroying brain cells¹² and damaging developing organs,¹³ and can lead to one of several serious life-long conditions for the child, that are together called Fetal Alcohol Spectrum Disorder (FASD).

Find out more about FASD

During childhood and teenage years, the brain and body are still developing. Alcohol – even small amounts - can affect memory function, reactions, learning ability and attention span.¹⁴

Evidence also reveals that children who start to drink by age 13 are more likely to go on to have worse grades, to skip school and even to be excluded from school.¹⁵

The risks associated with underage drinking are why England’s Chief Medical Officer recommends an alcohol-free childhood is the healthiest and best option. 

The risks of underage drinking

Alcohol support services

If you are concerned that you or someone you care about has a problem with alcohol there is a lot of help available. Here you can find useful links and phone numbers to get the support you need.

Support services