"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.
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