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AMA Report Shows Alcohol May Cause Long-Term Brain Damage

By Michael Stroh
THE BALTIMORE SUN -- Teens who joke about killing brain cells while downing beers may find the idea a bit less funny when they grow up.

A new report, released Monday by the American Medical Association, shows that adolescents and young adults who drink may risk long-lasting brain damage, especially when it comes to learning, memory and critical thinking.

And in some cases it may take as little as a few beers to cause harm, according to the report, which synthesizes nearly two decades of research on alcohol and the brain.

Public health officials have long known that the number of young people who drink is on the upswing. In 2000, 3.1 million people aged 17 and younger took a drink for the first time, according to the AMA report. Their average age: 12.

But scientists have only recently started to unravel the mystery of how alcohol affects the brain during youth. Now advances in neuro-imaging and other technologies are providing provocative -- and occasionally disturbing -- clues.

One of the first lessons is that the brain appears to be particularly susceptible to damage during high school and college -- the prime drinking years.

While the brain stops growing physically around the age of 5, its cells continue to refine and realign themselves until at least age 20.

“We know that some of the most critical wiring doesn’t even kick in until the second decade of life,” said Scott Swartzwelder, a neuropsychologist at Duke University and the U.S. Department of Veterans Affairs.

Teen drinkers appear to be especially vulnerable to damage in two regions: the hippocampus, a structure deep in the brain responsible for memory and learning, and the prefrontal cortex, which is tucked just behind the forehead and involved in decision making and reasoning.

For example, psychologist Michael De Bellis and colleagues at the University of Pittsburgh found that girls aged 14 to 21 with serious drinking problems had 10 percent smaller hippocampi than did non-drinking peers.

The researchers, who used magnetic resonance imaging to peek deep into their subjects’ gray matter, found girls who had been drinking longest had the smallest hippocampi.

But researchers are finding that it’s not just heavy or binge drinking -- officially defined as downing five or more drinks in quick succession -- that can have negative consequences.

Duke researchers, for example, found that when they gave adolescent rats -- often used as stand-ins for humans in alcohol research -- the rat equivalent of just two drinks, the rodents had a tougher time remembering how to exit a maze than did sober animals.

When the team repeated the study on a group of 21- to 24-year-old people, they found similar results: After only three drinks, for a blood-alcohol level slightly under the 0.08 legal limit, volunteers were 25 percent less accurate on memory tests.

The irony, said Swartzwelder, who was involved in both studies, is that the brain appears to be most vulnerable to alcohol during the very ages when it is being tasked the most: the high school and college years.

“It’s exactly the wrong time to do the most heavy drinking,” he said.

Other rat studies hint that heavy drinking during youth could have long-term consequences.