There is a link between brain size and excessive alcohol consumption and it is due more to genetics than to the consequences of alcoholism.
Excessive drinking may disturb the senses, but it cannot alone, be solely responsible for the shrinking of the brain. Although, there may be a link between brain size and alcoholism, a study recently published in the journal Biological Psychiatry shows that this volume loss may be due instead to common genetic factors.
“A lower brain volume in certain areas can predestine a person to consume more alcohol,” says Ryan Bogdan, lead author of the study.
Converging evidence of genetic factors
“Our study provides converging evidence that there are genetic factors leading to both reduced amounts of gray matter and excessive alcohol consumption. Although these results “do not rule out the hypothesis that alcohol abuse can further reduce brain volume, they do suggest that brain volume was smaller in the first place,” says Ryan Bogdan.
A lower volume of grey matter associated with heavy drinking was found in two regions of the brain that are important for emotions, memory, reward, cognitive control and decision-making.
But medical imaging studies have also shown that this reduced volume was predictive of alcohol initiation in adolescence. And to confirm the genetic nature of the relationship between small brain size and heavy drinking, researchers compared the brains of twin brothers and discovered that within the same family the brain size was the same, regardless of whether they drank heavily or not.
This led Ryan Bogdan’s team to say that there is evidence that the lower amount of grey matter is a pre-existing vulnerability factor to heavy drinking, rather than a consequence of it.