MONDAY, Sept. 21 (HealthDay News) -- In a study that shows that doing JELL-O shots is never a good idea, adolescent rats that consumed alcohol-laced gel were more likely to make risky decisions long after the alcohol had worn off.

Though the research was done with animals, researchers said human teenagers who drink to excess could experience similar, long-lasting effects.

In the study, researchers assigned young rats to one of two groups. The first had access to an alcohol-laced gel for 20 days. The rats liked the taste and consumed large quantities of the substance, the equivalent of several shots of whiskey daily in a human. A second group of rats was given no alcohol.

After three weeks and again at three months -- long after the rats had sobered up and were considered adults -- the rats that had consumed alcohol when they were younger were more likely to make poor decisions.

"We believe it's an effect of alcohol on the developing adolescent brain that causes them to perform differently in decision-making tasks later on," said senior study author Ilene Bernstein, a psychology professor at the University of Washington in Seattle.

The report will be published in the Sept. 21-25 online early edition of the Proceedings of the National Academy of Sciences.

Previous studies have shown that early alcohol consumption is a risk factor for later substance abuse and other risky behavior, Bernstein said.

But researchers have not been able to establish if the poor decision-making and propensity for risk-taking in adulthood was a personality trait in people, or if the alcohol itself could have an impact on the teenaged brain, altering behavior and thought processes down the line.

"We believe their brains have been changed in such a way that when it comes to making decisions, they are less able to make good decisions," Bernstein said.

In the experiment, hungry adult rats were given the choice between pressing two levers: the first lever dispensed two sugar pellets each time, while the second lever dispensed four pellets, but not all of the time. Sometimes, nothing came out.

The rats that had been exposed to alcohol were more likely to continue to press the lever with the uncertain outcome, even though over time it resulted in less pellets.

"For some reason, the rats were choosing the risky lever at higher levels than the controls, even when it was costing them," Bernstein said. "They were not performing optimally. They were making risky, poor choices."

A similar effect may be playing out in teenagers who drink to excess, Bernstein said.

Alcohol is known to be toxic during early development. Alcohol consumption by mothers during gestation can cause birth defects and fetal alcohol syndrome.

"The adolescent brain is still developing and growing," Bernstein said. "The same mechanisms that impair brain growth early on may also leave the adolescent brain vulnerable to alcohol effects. Perhaps the brain has a longer period of vulnerability than most people have appreciated."

It's well known that people under the influence of alcohol or drugs take bigger risks, said Dr. Adam Bisaga, an associate professor of clinical psychiatry at the Columbia University College of Physicians and Surgeons, in New York City.

One of the concerns with teens is that their lack of maturity and experience may contribute to their making very bad, dangerous decisions when they're under the influence, Bisaga said.

"This study goes beyond that even, showing that it's not just when you are getting drunk or high that you make bad decisions, but there could be some long-lasting effects of using alcohol on behavior," Bisaga said.

Teen alcohol use is a serious public health problem, Bernstein said. The earlier the exposure, the more likely someone will have a substance abuse problem later in life.

"This research raises a concern that if the brain is permanently changed by alcohol we need to place more emphasis on preventing adolescent alcohol use," Bernstein said.

More information

The U.S. National Institute on Drug Abuse has more on teens and substance abuse.

SOURCES: Ilene Bernstein, Ph.D., professor, psychology, University of Washington, Seattle; Adam Bisaga, M.D., associate professor, clinical psychiatry, division on substance abuse, Columbia University College of Physicians and Surgeons, New York City; Sept. 21-25, 2009, Proceedings of the National Academy of Sciences

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