The science of what alcohol does to the brain at three most at-risk ages

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Alice Hall
·7 min read
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New research, which was published in the BMJ last week, stated that over-65s, youngsters in their late teens and babies in the womb are most at risk of the harmful effects of booze
New research, which was published in the BMJ last week, stated that over-65s, youngsters in their late teens and babies in the womb are most at risk of the harmful effects of booze

Most of us will be able to remember our first sip of alcohol: maybe it was a secret swig of whisky from a bottle in our parents drinks cabinet, or a lukewarm beer smuggled into a friend's sleepover. But despite its prevalence, it turns out drinking alcohol as teenagers could be more problematic than we think. According to researchers from Kings College London, adolescence is one of the three key life stages when alcohol is most damaging to the brain. 

The research, which was published in the BMJ last week, stated that over-65s, youngsters in their late teens and babies in the womb are most at risk of the harmful effects of booze, because these life stages correlate with "dynamic brain changes". And even casual drinkers need to be aware: although the negative effects of alcohol are traditionally associated with binge drinking, the scientists warn that even moderate drinking is linked with small, but significant, loss of brain volume in midlife.

With more of us than ever hitting the bottle during lockdown, this makes for scary reading. Figures released in October by the University of Glasgow show that one in five people drank four nights a week during lockdown with binge drinking rising the most for women and for those with a university degree. Meanwhile a recent study from the Centre for Ageing Better found 32 per cent of people aged between 50 and 70 have been drinking more as a result of the pandemic. 

As Professor David Nutt, author of Drink?: The New Science of Alcohol and Your Health, says, “there’s no level of alcohol consumption that is without risk.” But how does alcohol affect our brain in each of these high risk age groups? We’ve broken it down…

Over 65s

Binge drinking has been associated with an increased risk of dementia - Alamy 
Binge drinking has been associated with an increased risk of dementia - Alamy

Alcohol use disorders were "shown to be one of the strongest modifiable risk factors for all types of dementia" in older people, according to King's researchers. Indeed, Prof Nutt agrees. In his book Drink?, he writes: "It’s thought at least one in five cases of dementia is probably due to alcohol... In fact, the number of people living with it is expected to triple by 2050. And it’s been suggested that women may experience brain damage at lower levels of alcohol intake than men."

This link is present before the age of 65 too. According to a study published in The Lancet Public Health journal, of the 57,000 cases of early-onset dementia (before the age of 65), 57 per cent were related to chronic heavy drinking. This is known as alcohol-related brain damage (ARBD) or alcohol-related brain injury (ARBI): around one in 10 people with dementia have some form of ARBD. 

Prof Nutt explains this is partly due to the "direct neurotoxic effect" of the alcohol itself. In old age, alcohol "depresses the brain function," which is already impaired. "There are also indirect effects, such as the increased risk of stroke, diabetes and high blood pressure that comes from drinking. All of these raise your risk of dementia. Finally, you’re more likely to have an accident after drinking – and head injury is a huge risk factor for dementia," he adds.

Figures released in 2016 showed that more over-60s were being hospitalised for alcohol-related brain damage, a condition known as Korsakoff syndrome, which is similar to dementia; it involves acute loss of memory caused by long-term heavy drinking and is irreversible. At the time, numbers were small but the trend was pointing sharply upwards: just 149 over-60s were admitted with the syndrome in 2005-06, but in 2014-15 the figure was 376.

Although the evidence around dementia and alcohol is contradictory, experts are in agreement that moderation is key. A 2011 report from the Royal College of Psychiatrists said people over 65 should drink a maximum of only 1.5 units of alcohol a day - the equivalent of just over about half a pint of beer or a small glass of wine. The report stated that older drinkers are less able to process alcohol and the drink might also interact with medication they may be taking for other ailments. 

Adolescents 

Teenagers who binge drink may be more prone to anxiety later in life  - Alamy 
Teenagers who binge drink may be more prone to anxiety later in life - Alamy

Worryingly, more than 20 per cent of 15 to 19-year-olds in European and other high-income countries report at least occasional binge drinking.  Tony Rao, a researcher in alcohol use and dementia at King’s College London, said that although "alcohol use in teenagers is also accompanied by the use of drugs such as cannabis", studies that take these factors this into account have some intriguing findings.

"Teenagers who engage in binge drinking - that’s the equivalent of 4 pints of beer for males and 3 for females - show more problems with memory and problem solving than non-drinkers. This drinking pattern is also accompanied by a reduction of nerve growth in areas such as the hippocampus, a key area for memory storage," he says. "There is also likely to be more widespread disruption of connections between other brain areas. The net outcome is often reduced educational achievement and problems in the way that these teenagers interact socially with their peers”

Sleeping patterns can be affected, too. In Drink? Prof Nutt explains that one of the strangest sleep problems he has come across linked to alcohol is Sleeping Beauty syndrome, or Kleine-Levin Syndrome. It usually affects teenagers and young people fall asleep for three or four days at a time. “We think it might come from some form of inflammation - perhaps a virus - damaging the wakefulness-promoting centres of the brain,” he says. 

Alcohol also encourages teenagers to take dangerous risks. The prefrontal cortex, the part of the brain associated with things like rational thinking, planning, personality, impulse control and language, is affected by the consumption of alcohol (it’s the main reason why we tend to make poor decisions when we're drunk). When a developing adolescent brain comes into contact with alcohol, not only is the pre-frontal cortex still in the process of maturing, but the alcohol might damage these brain cells. As Prof Nutt says, “risky behaviour under alcohol leads to many harms, such as car crashes.”

There's also the risk of developing psychiatric disorders, and dependence on alcohol, later in life. One 2015 study published in the journal Neurobiology of Disease exposed rats to intermittent doses of alcohol during adolescence. They found evidence that these rats were more likely to experience symptoms such as anxiety later in life. 

Babies in the womb

 Heavy alcohol use during pregnancy can cause fetal alcohol spectrum disorder (FASD), which is associated with babies having a smaller brain volume and problems with memory or thinking - Jamie Grill/Tetra images RF
Heavy alcohol use during pregnancy can cause fetal alcohol spectrum disorder (FASD), which is associated with babies having a smaller brain volume and problems with memory or thinking - Jamie Grill/Tetra images RF

It’s no secret that alcohol is harmful for unborn babies. Heavy alcohol use during pregnancy can cause fetal alcohol spectrum disorder (FASD), which is associated with babies having a smaller brain volume, childhood brain damage, problems with memory or thinking and poor behaviour. Research undertaken in 2018 found that women drinking during pregnancy could be causing birth defects in one in six children. 

It’s still not understood exactly how alcohol causes the specific problems seen in FASD. Experiments in animal models have shown that alcohol exposure prompts neural crest cells, which normally develop into facial structures and various brain cells, to die prematurely. It also slows down the reproduction of neural stem cells, which drive the development of the fetal brain.

Despite the risks, globally, about 10 per cent of pregnant women consume alcohol with rates considerably higher in European countries. Typically, some women have allowed themselves a small tipple or two, but in January this year new research showed that even occasional drinking during pregnancy may lead to poorer cognitive function and lower birth weight. “This was a study that pulled together lots of different pieces of evidence, which all say more or less the same thing: women should avoid alcohol pre-conceptually and entirely throughout pregnancy,” Clare Livingstone, the Royal College of Midwives’ (RCM) lead policy advisor on alcohol in pregnancy, told the Telegraph. 

Drink?: The New Science of Alcohol and Your Health by Professor David Nutt. Buy now for £9.99 at books.telegraph.co.uk or call 0844 871 1514