A recent University study shedding light on why some people become binge-drinkers could be a pivotal tool in preventing future alcohol addiction.

The study, led by U of C psychiatry professor Andrea King, the director of the Substance Abuse Clinic at the University of Chicago Medical Center (UCMC), suggests heavy drinkers are more sensitive to the euphoric effects of drinking and less sensitive to its sedative effects. These results challenge widely held notions about alcohol addiction.

“The prevailing theory was that people at risk for alcoholism were those who showed little response to alcohol, so they needed to drink a lot in order to get the effects,” King said. Instead, the study suggests that those more affected by alcohol are more likely to binge-drink because of an increased sensitivity to its rewarding effects.

The study surveyed nearly 200 subjects between the ages of 21 and 25, who were divided into “heavy” and “light” drinkers by alcohol consumption habits. Subjects consumed a placebo, a low-alcohol-content drink, or a high-alcohol-content drink, each flavored to mask the alcoholic content.

When the subjects were breathalyzed and reported their moods, heavy drinkers reported experiencing more positive and rewarding effects and fewer sluggish effects.

“You can take a 150-pound male light drinker and a 150-pound male heavy drinker and give them each the exact same dose of alcohol, but their brains respond very differently to this substance, hence the divergent experiences and mood reports after consumption,” King said.

After the initial laboratory tests, the study followed subjects for two years. By comparing long-term results of each subject’s drinking behavior with his original response to alcohol in the laboratory tests, researchers found that an individual’s initial response can predict his future drinking behavior.

To further examine the correlation between alcohol sensitivity and binge-drinking, the researchers will continue their study, following up on participants over nine years.

The study was published last week in the General Archives of Psychiatry.