Science in the Triangle

Sobering news for underage drinkers: adolescent binge drinking can lead to irreparable brain damage as an adult.

That’s what a new study from the Bowles Center for Alcohol Studies at UNC-Chapel Hill’s School of Medicine found.

It also found striking figures as to just how many adolescents are binging when they drink. Forty-four percent of college students reported heavy alcohol intake in the last two weeks, 28 percent of twelfth grade seniors, 22 percent of tenth graders, and, finally, 12 percent of eighth graders.

Adolescence, between ages 12 and 20, is a period of critical growth for the human brain. The adolescent brain is much more sensitive to changes induced by alcohol than a fully matured one. With so many teens drinking, the country’s youth are at risk for under-developing their adult brains, said Dr. Fulton Crews, the director of the Bowles Center and the lead pharmacologist on the study.

“We found that alcohol exposure changes genes in the brain,” Crews said. “And actually shrinks part of the forebrain, resulting in a loss of acetylcholine molecules.”

Acetylcholine is a key neurotransmitter involved in both the central and peripheral nervous systems. He said alcohol can also heighten impulsivity in adolescents—not just in the moment of intoxication, but down the road.

“As you mature, you become less impulsive,” Crews said. “And if you’re drinking young, it seems to disrupt that maturation. If you started drinking as an adolescent, you’re more likely to get in a fight.”

However, Crews makes a distinction between impulsivity and aggression. Aggressive people, he said, are angry and violent, whereas impulsive people have a hard time controlling their immediate urges.

The next logical step, Crews said, is to examine whether adolescent binge drinking increases chances of depression, anxiety or personality disorders.

“I think it does, but right now we really don’t have the data to back it up,” he said. “What we do have makes us lean that way.”

The study can be found in the April 2011 edition of Alcoholism: Clinical and Experimental Research.

Dr. Martin Styner is the co-director of UNC’s Neuro Image Research and Analysis Laboratories (NIRAL). Styner helped Crews develop computer tools and MRI programs to measure which parts of the brain are affected by alcohol. The statistics on adolescent drinkers did not surprise him.

“Adolescents would be more likely to drink because of the current social acceptance of it,” he said.

Currently, though, there have been no actual long-term tests on humans. All MRI data instead came from rats, Styner said. He claims the research with regards to adolescent binge-drinking is just beginning for him and his team. Next, they will investigate the connectivity between different parts of the brain and how drinking can spawn a chain collapse in neural networking.

Crews said he hopes this information will help prevent teens and adolescents from drinking so much. He also said it might motivate parents to see underage drinking as something more than what he called “transient intoxication”.

“I read stories where parents say, ‘the problem with underage drinking is the traffic accidents’,” Crews said. “‘And kids do it because it’s forbidden fruit, so I’m going to let them drink in my house’. But it’s also hurting their brain, and they need to hear that.”

Carrboro Police Sgt. Chris Atack said the hardest part of enforcing underage drinking laws is a general lack of adolescent supervision by parents.

“I do it myself with my 4-year-old,” Atack said. “You think they’re older or more mature than they really are.”

From a law enforcement standpoint, he said, it’s very difficult to control what goes on inside a private residence because officials are rarely alerted until it becomes a problem. Atack said he, too, was not stunned by the study’s statistics on how many adolescents binge drink.

“It is what it is,” he said. “In a lot of ways it’s unfortunate, but it’s not surprising.”

Crews said he absolutely supports the drinking age being 21, for medical reasons. Right now, the law is in place only because of the amount of how many people are killed by drunk driving, he said. It has nothing to do with biology or neurological effects, he said, and that’s something he wants to see change.

“I have kids of my own,” Crews said. “I’ve been lucky that they don’t have drinking problems. I’m not sure I can say I controlled all aspects of their development.”