Alcohol cheers some people while it pushes others into depression. This could predict who is likely to have a problem with drinks those who get high on alcohol are far more likely to become addicted.
Though often described as a depressant, alcohol contains a mixture of stimulant and sedative effects, with some treating it as a social lubricant and others as a downer.
It had been suggested that people who get less affected by alcohol drink more heavily to compensate, the journal Archives of General Psychiatry reports.
But the new study from the University of Chicago suggests heavy drinkers are actually more sensitive to the euphoric effects of drink and less sensitive to its sedative side.
This means they get more bang for their bucks and are more attracted to alcohol, researchers believe, according to the Telegraph.
Andrea King and her team from Chicago recruited nearly 200 subjects aged between 21 and 35, and divided them into heavy and light drinker groups.
The heavier group consumed 10 to 40 drinks a week and bingeing at least once averaging more than five drinks in two hours. Light drinkers had between one and five drinks and rarely binged.
They were given one of three drinks; a placebo, a low alcohol drink and a high alcohol drink, each flavoured to mask the content. None of the subjects was even aware the study concerned alcohol.
Afterwards they filled out a survey describing their moods and were breathalysed.
The light drinkers were more sensitive to the overall effects of the drink, but described their feelings as sluggish and sedated. Conversely, heavy drinkers reported positive and rewarding effects.
King said: They both had very similar blood alcohol concentration curves, but the effects of alcohol were markedly different.