Researchers from the University of Chicago looked at whether people get a sedative or a stimulatory effect from alcohol said those in the latter category are more likely to drink heavily.

In the study, published in the journal Alcoholism: Clinical & Experimental Research, researchers looked at how drinkers were affected by alcohol.

Drinkers' reported their moods after alcohol, and they were tested to see how their body reacted to moderate-to-high doses of alcohol.

Alcohol works on different brain chemicals that may be more or less sensitive to various amounts of alcohol in the blood

Raymond Anton, Medical University of South Carolina

Thirty-four drinkers aged between 24 and 38 were studied.

Half drank five or less alcoholic drinks per week while the heavy drinkers regularly had 10 or more drinks.

They were either given two different doses of alcohol (the equivalent of two or four drinks) or a drink which just had an alcohol smell and taste.

They then filled out questionnaires, and their heart rate, blood alcohol and cortisol (a stress hormone) levels were tested.

Euphoria

Heavy drinkers showed increased stimulation and euphoria when blood alcohol concentrations rose.

They also enjoyed the experience and wanted to carry on drinking.

Light drinkers showed increases in sedation and did not report stimulation or positive mood changes.

They also had increases in cortisol levels after drinking, whereas the heavy drinkers did not.

Andrea King, a psychologist and assistant professor in the university's department of psychiatry who led the research, said: "A person who feels enhanced euphoria and stimulation when drinking alcohol may be more likely to continue to consume alcohol during the drinking bout.

"Since they may be more sensitive to the rewarding effects of alcohol, they may be more vulnerable to developing habitual, heavy drinking patterns which would increase their chances of having eventual alcohol problems and negative consequences related to drinking."

Raymond Anton, professor of psychiatry and scientific director of the Alcohol Research Center at the Medical University of South Carolina, said: "Alcohol works on different brain chemicals that may be more or less sensitive to various amounts of alcohol in the blood.

"It is likely that different people have different brain chemistries, making them more or less sensitive to one or the other of these effects, stimulation or sedation, from a given dose of alcohol."

Dr Jane Marshall, a consultant psychiatrist specialising in addictions at the South London and Maudsley NHS Trust, said developing drugs for patients to blunt the feelings caused by alcohol could help people who had addictions or cravings.

"I think the use of pharmacological solutions will probably be used alongside psychosocial treatments such as cognitive behavioural therapy."