The Age of the Frontal Lobe: how alcohol affects the brain area most responsible for us being human
You may have wondered how your grey cells are affected by how much you drink. You may have wondered if some people are born to be alcoholics, or whether it is just an unfortunate series of life experiences and personal decisions. Scientists are undertaking hundreds of studies into the relationship between alcohol and our brain structure – a few examples of which will be reviewed here.
Generally speaking, the study of the neuroscience of alcohol tends to look at the pathology of drinking – in other words, excessive drinking of alcohol. This is broadly understood as regularly drinking more than 14 units every week.[1] To test how alcohol affects the brain, many studies use a sliding scale of how much alcohol people drink a week to observe what different effects are seen. People of course tend to underreport how much they’ve drunk – the famous influence of social desirability – so this is always something to bear in mind with this area of research.
This review will be split into three parts, each looking more closely at the genetics and brain differences involved in our behaviour around alcohol. Most studies look at the brains of people with alcoholism, but research is now starting to look at how the brains of moderate drinkers may also be affected by alcohol. This is Part III: ‘The Age of the Frontal Lobe: how alcohol affects the brain area most responsible for us being human.’
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The frontal lobe is considered by many to be what distinguishes us from animals. As far back as 1928, psychologists were describing the age of humanity as the ‘age of the frontal lobe’.[2] Involved in crucial mental processes like problem-solving, planning, memory, decision-making, and motivation, the frontal lobe is integral to the functioning of our daily lives. It is also the largest and most complex region of the brain. Knowing then that alcohol affects the brain, how does the frontal lobe become implicated in this relationship?
Though it was published several years ago, we come to this useful study which compiled a huge amount of evidence into the brain structures involved in alcoholism. [3] Pulling together results from a number of disciplines, the evidence points to the frontal lobe as being a particularly hotspot for the detriments of heavy drinking. These disciplines included morphology (the shape and structure of the brain), neuropsychology (how brain injuries or illnesses affect how we think and behave), and neurophysiology (the function of the nervous system). In particular, two different types of brain imaging techniques showed that the brains of alcoholics are less able to use glucose, particularly in the frontal lobe. Alongside this, their brains have a lower amount of cerebral blood flow. Together, this means that the activity of the frontal lobe – and all of the complex functions that it is involved in – is diminished.
Several other notable effects have been observed in the brains of alcoholics, but this study raises an important question: how much of these brain deficits are caused by drinking so much alcohol – nurture – and how much are alcoholics born with these deficits already – nature? There is even the possibility that people with certain brain differences already are particularly susceptible to the damaging effects of alcohol. Although it is probably likely that the heavy drinking has caused these deficits, we cannot know for sure. Because of the way these studies are set up, it becomes difficult locating whether these differences predate a person’s fall into alcoholism. Researchers mainly test people who are already deep in alcoholism, rather than people who will become alcoholics in the future – because it is currently impossible to tell. This kind of understanding of what brain differences increase one’s likelihood to alcoholism will come from studies similar to the one featured in Part II, but there is an important ethical concern as we continue researching this. On one hand, if we could effectively tell which people would become alcoholics early in their life by their brains alone, this could help with early interventions. But it may also lead to a scary genetic determinism. This in turn would lead to stigmatisation and despondency, with sinister implications for life insurance and beyond. On a more personal level, learning that you are destined be an alcoholic at age ten can’t be the most heartening discovery. Opinions on what we should biologically know and leave unknown is conflicting and ever-increasing as our research capacities into brain and genetics expands.
Thus, despite the exact origins of these frontal lobe deficits in alcoholics still being fairly unclear, these findings are still crucial in developing treatments for people with alcoholism. They will be particularly helpful with rehabilitative programmes – for example, treating the glucose deficiency in a person’s frontal lobe will make it more likely that they will able to better engage with treatment. Ultimately, the more the specific brain areas are identified in relation to alcohol use, the better understandings and treatments will be. And an element of caution is noted for future research into the brains and genetics of people with alcoholism, lest it becomes too deterministic.
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Follow through to Part I: ‘An Aperol a Day’ and Part II: ‘Alcoholism: is it in your genes?’
References
[1] NHS (n.d.) Alcohol Misuse. NHS. Available at: https://www.nhs.uk/conditions/alcohol-misuse/
[2] Tilney, F. (1928). The brain from ape to man. Hoeber.
[3] Moselhy, H.F., Georgiou, G., Kahn, A. (2011) Frontal lobe changes in alcoholism: A review of the literature. Alcohol and Alcoholism. 36, 5. 357–368