Just a few sessions of heavy drinking can damage someone's ability to pay attention, remember things and make good judgments, research shows.
Binge drinkers are known to be at increased risk of accidents, violence and engaging in unprotected sex. But the study is the first to identify brain damage as a danger of consuming more alcohol than official safe limits.
The study was undertaken by two experts in alcohol's toxic effects on the brain: Professor Fulton Crews, director of the Bowles Centre for Alcohol Studies at the University of North Carolina, and Dr Kim Nixon of the department of pharmaceutical sciences at the University of Kentucky.
They reviewed previous studies in which rats were used in experiments to examine the impact of binge drinking and then related those findings to humans. For four days in a row the rats were given the same amount of ethanol that someone imbibing 15 units of alcohol - about seven pints of normal-strength beer - would consume in one drinking session. Losses in key mental abilities were noted in the weeks after the experiment had ended.
"It is fair and credible to extrapolate the research findings from tests on rats to humans," said Dr Jonathan Chick of the alcohol problems service at the Royal Edinburgh hospital, who is the chief editor of Alcohol and Alcoholism."From this research we can infer that humans who have a few heavy drinking sessions in a row may sometimes undergo subtle brain changes which make it harder to learn from mistakes and to learn new ways of tackling problems because their brain function has been subtly impaired."
The research also suggests that loss of brain function in people under 20 brought on by binge drinking increases their chances of becoming alcoholics in later life, Chick added.