What are the effects of alcohol on the brain?
Many of us enjoy a glass of wine or a pint, but what is actually happening to our brain cells when we drink alcohol?
The 80-90 per cent of UK citizens who aren’t tee-total will be familiar with the short-lived feelings of relaxation and Dutch-courage experienced after a few alcoholic drinks, but what does this clever potion do to the brain to evoke these feelings?
Brain function is underpinned by the action of neurotransmitters, various chemical signals which are released by brain cells as a means of communication with each other. Some neurotransmitters increase the action of their recipient (excitatory), while others decrease the activity of the brain cells they contact (inhibitory).
GABA - an acronym for a chemical whose name is far too long to be worth remembering - is an inhibitory neurotransmitter that slows down brain function resulting in drowsiness, relaxation and anesthesia (pain relief). These effects should resonate if you drink alcohol because alcohol induces these feelings by increasing the action of GABA.
Alcohol simultaneously decreases the levels of glutamate – an excitatory neurotransmitter – which also indirectly leads to the calming of the nervous system.
The happy chemical
Aside from a simple bipolar inhibitory vs excitatory system, neurotransmitters contribute to complex neuronal networks (interconnected brain cells). One such system is the reward circuit, central to pleasure and addiction, which is brought to life by the neurotransmitter dopamine.
The joy an intoxicated brain experiences in the midst of sweaty bodies and sticky carpets in a nightclub surprisingly isn’t owed to the picturesque setting, but to alcohol’s influence on the dopaminergic system. Like the promoter beckoning from the club entrance, alcohol promotes the release of dopamine leaving you happy and eager for another hit; this is the basis of alcoholism. Alcoholics keep chasing the hit of dopamine that follows a shot of alcohol because of the subsequent activation of the reward circuit and the pleasure this evokes.
More like this
Practise makes perfect
Speaking of repeated exposure: with most things, improvement comes with practice and alcohol is no exception. By improve, we mean the body (including the brain) improves its ability to withstand more alcohol before the effects are visible; a phenomenon known as ‘tolerance’. The brain cells get more used to being exposed to alcohol and so don’t react to it as easily – they have developed a tolerance to it. This explains why new drinkers are on the floor after a few cans, whereas it takes much more alcohol to bring down the seasoned drinker.
The morning after…
They say no good deed goes unpunished; an elated, drunk state evolves overnight into a banging headache, nausea and, for some, feelings of anxiety. It takes the body two hours to clear a medium glass of wine or a pint of beer, so the body’s clean-up mission continues long after the enjoyable effects of alcohol have worn off and the drinker is given a harsh physical reminder of why alcohol is classified as a poison.
What happened last night?
Although they are intrinsically connected, different brain areas, generally speaking, undertake different tasks. The hippocampus is a region of the brain devoted to memory in which events get converted into short-term memories and then committed to long-term memories, allowing them to be reminisced upon in years to come. But alcohol interferes with the function of the hippocampus preventing the establishment of long-term memories, making it responsible for periods of blackouts that sometimes occur during a heavy drinking session. The memories that are lost are only those that would have been formed during the individual’s time under the influence.
Look to the future
Unfortunately, blackouts may just be the tip of the iceberg when it comes to alcohol-induced memory loss. High alcohol intake over a prolonged period can lead to lasting brain damage which can trigger the onset of a number of dementias. Dementia is a broad term used to describe symptoms of memory loss and confusion which can be caused by a multitude of diseases such as Alzheimer’s Disease. Alcohol-related dementia and Korsakoff’s Syndrome are two types of dementia which are the direct result of alcohol abuse, while a high intake of alcohol has been linked as a risk factor to most types of dementia.
A wine a day keeps the doctor away
However, the relationship between dementia and alcohol is far from simple; drinking smaller amounts of alcohol can actually have an inverse relationship with dementia. Studies have concluded that drinking up to three glasses of wine a night can reduce the risk of the drinker developing dementia. Although research into the mechanisms of this remarkable finding is ongoing, scientists are yet to uncover the reason why a mild to moderate intake of alcohol could help protect the brain.
So next time you’re in the pub enjoying a well-earned drink, spare a thought for the complex goings on behind the opaque screen of your skull.
If you are concerned that you or a loved one has a problem with alcohol, please contact your GP or ring Drinkline (0300 123 1110) for confidential, free advice.
- Try your first 6 issues for just £9.99 when you subscribe to BBC Science Focus Magazine.
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.
- Stay up to date with the latest developments in the worlds of science and technology.