Scans reveal certain areas of the brain shut down when alcohol is consumed.
Researchers at the UNSW School of Psychology have pinpointed exactly why people get violent and aggressive after drinking alcohol.
It’s often been theorised that alcohol-related aggression is caused by changes in the prefrontal cortex, however, there is a lack of substantial neuroimaging evidence to support this idea.
The study, led by Associate Professor Thomas Denson, used magnetic resonance imaging (MRI ) scans to measure blood flow in the brain to better understand why this aggression takes place. Researchers found the brain areas normally involved in tempering aggression – the prefrontal cortex – shuts off when people drink. This happens after just two drinks.
During the study, Denson’s team recruited 50 healthy young men. The men were given two drinks containing vodka or a placebo mixer without any alcohol. Then they were asked to perform certain tasks while lying in an MRI scanner.
Health experts have renewed calls for the drinking age to be raised to 21 despite a new survey finding fewer teenagers are drinking than ever before.
Researchers discovered that being provoked had no influence on the participant’s neural responses.
However, when behaving aggressively, there was a dip in activity in the prefrontal cortex of the brains of those who had consumed alcoholic drinks.
This dampening effect was also seen in the areas of the brain that are involved with reward.
“Although there was an overall dampening effect of alcohol on the prefrontal cortex, even at a low dose of alcohol we observed a significant positive relationship between dorsomedial and dorsolateral prefrontal cortex activity and alcohol-related aggression,” says Denson.
“These regions may support different behaviours, such as peace versus aggression, depending on whether a person is sober or intoxicated.”
Denson hopes the research will eventually led to reducing alcohol-related harm.
“We encourage future, larger-scale investigations into the neural underpinnings of alcohol-related aggression with stronger doses and clinical samples. Doing so could eventually substantially reduce alcohol-related harm,” adds Denson.
The findings were published in the journal Cognitive, Affective, & Behavioral Neuroscience.
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