How Teen Drinking May Affect Brain Growth

By Kelly Burch 04/03/19

Researchers investigated whether drinking alcohol during the teen years stunted brain growth.

teens drinking alcohol

Drinking alcohol could stunt brain growth in teenagers and increase their risk for problematic drinking in the long term, according to a recent study

The findings were published in the journal eNeuro. To examine the effects of alcohol on brain development, scientists allowed rhesus macaque monkeys to drink as much as they wanted. They tracked how much the monkeys ate and drank, and used MRIs to measure their brain growth. 

“Heavy alcohol reduced the rate of brain growth” by 0.25 milliliters per year for every gram of alcohol consumed per kilogram of body weight, the researchers found. Smaller brain volume can be associated with less cognitive abilities, because there are fewer connections in the brain. 

During the teen years, the brain is rapidly growing and developing, which may explain why teens are particularly vulnerable to the brain-stunting effects of alcohol. 

“The transition from adolescence to adulthood is associated with brain remodeling in the final stages of developmental growth. It is also a period when a large proportion of this age group engages to binge and heavy alcohol drinking,” study authors wrote.

The stunted growth could lead to long-term cognitive effects, although further studies would be needed to examine that theory. 

“This is the age range when the brain is being fine-tuned to fit adult responsibilities. The question is, does alcohol exposure during this age range alter the lifetime learning ability of individuals?” lead author Dr. Tatiana Shnitko said to The Journal. 

In addition to affecting brain volume, drinking during the teen years also seemed to be associated with heavier drinking later in life in the monkeys that were studied. 

“Thus, developmental brain volume changes in the span of late adolescence to young adulthood in macaques is altered by excessive alcohol, an insult (the cause of some kind of physical or mental injury) that may be linked to the continuation of heavy drinking throughout later adult life,” they wrote. 

This indicates that early drinking could lead to lifelong problems in humans’ drinking patterns as well. 

While not all the effects from monkeys can be extrapolated to humans, studying the effects of alcohol on primates' brains is a powerful tool for researchers. Study author Christopher Kroenke said that using monkeys allowed researchers to control for factors and focus on the specific effects of alcohol use. 

“Human studies are based on self-reporting of underage drinkers,” he said. “Our measures pinpoint alcohol drinking with the impaired brain growth.”

The amount of alcohol that affected brain health would be equivalent to about four beers a day. 

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Kelly Burch writes about addiction and mental health issues, particularly as they affect families. Follow her on TwitterFacebook, and LinkedIn.