Alcohol is deeply rooted in our cultures and habits, and in most Western countries, its significant economic weight grants it a much more favourable legal status and social perception than other drugs.
This is likely why teenagers consider it the safest drug they can take, despite the fact that it is the leading risk factor for premature death and disability in people aged 15-49, and that myths like “a glass of wine a day is good for your health” have been thoroughly debunked. This perception is only reinforced by its central role in many traditions and celebrations, which link it to social success.
Alcohol is the most widely consumed drug among young people in Western countries. In Europe, around 8 out of 10 students aged 15-16 have had a drink in the last year. Even more alarming is the early age of alcohol onset – 33% of under-13s in various European countries have already consumed alcohol – as well as high rates of binge drinking, which 34% of 15-16 year olds in Europe report doing in the last month.
Binge drinking, the most common form of drinking among 15-19 year olds, involves ingesting large amounts of alcohol in short periods of time: usually 5 or more drinks within a period of 2-3 hours. This kind of drinking is typical of teenage parties, as well as holidays and festivities like weddings, Christmas and New Year’s Eve.
Saturating the liver
Many of us know the negative consequences of consuming alcohol, such as getting into fights, risky sexual behaviour, or traffic accidents. However, fewer of us consider how a few binge drinking sessions can affect the brain, especially when it is still developing.
To understand these effects, we need to look at two key elements: how alcohol is metabolised, and how it affects the developing adolescent brain.
Alcohol is mainly metabolised in the liver, which processes the drink after it has been absorbed from the digestive tract. There, alcohol is broken down by various enzymes, transforming it into less toxic substances that the body can then eliminate. When alcohol is not fully metabolised, it passes into the brain, disrupting the delicate balance of neurotransmitters that regulate its functioning.
We can think of the liver as a sponge that absorbs alcohol. However, when it becomes saturated, it loses this capacity for absorption and elimination, causing the well known effects of drunkenness: disinhibition, euphoria, lack of coordination, and so on.
Vulnerable teenage brains
Unfortunately, alcoholic beverages not only have temporary impacts on the functioning of our brains, they also have long-lasting effects on various aspects of the nervous system, and can also affect the immune system, triggering inflammatory processes that damage brain development.
It is important to note that during its development – up to the age of 25-30 – the brain is at its most vulnerable to the effects of drugs. During this period, alcohol is particularly harmful, as it can interfere with two key neurodevelopmental phenomena: myelination, the process by which neurons coat their axons with myelin to improve signal transmission, and synaptic pruning, which removes unnecessary neuronal connections to optimise brain function.
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Moreover, these changes cause certain areas of the brain to mature earlier than others. Specifically, the areas responsible for reward processing (such as the ventral striatum) develop more quickly than those responsible for decision-making and long-term planning (such as the prefrontal cortex). This mismatch between the development of the brain’s reward, impulse control and decision-making systems may explain why adolescents are more likely to engage in risky behaviour.
Assessing the damage
Neuroimaging studies have shown that the brains of young people who often engage in binge drinking are structurally and functionally different.
Among the most prominent structural findings is reduced integrity of white matter, an element of the nervous system that is crucial for efficiently transmitting information.
Alterations in grey matter have also been identified, with increases or decreases in areas such as the ventral striatum, anterior cingulate cortex and medial frontal gyrus, which are critical for reward processing, monitoring of important stimuli and working memory.
In terms of functional connectivity – the way different areas of the brain interact – binge drinking is associated with abnormalities in the configuration of several networks, such as salience and/or frontoparietal networks. These guide our attention to where it needs to be, and regulate our behaviour to achieve both short and long term goals.
In addition, neuroimaging studies show excessive activation in brain structures involved in impulse control, decision-making, and processing of alcohol-related stimuli.
We have to stress the relationship between the age of starting alcohol consumption and later problems, which can include substance abuse, early onset dementia, or heart disease. The data is clear: the earlier someone starts drinking, the higher their risk of developing these conditions.
This highlights the fact that there is no such thing as a healthy dose of alcohol, and no such thing as harmless binge drinking. It is crucial that we pay especially close attention to teenage drinking.
