US scientists may have found a gene that determines how strongly drinkers feel the effects of alcohol, which could indicate susceptibility to alcohol abuse.

In a genetic study of 367 subjects aged 18 to 29, researchers at the Ernest Gallo Clinic and Research Center in California found that a DNA sequence variation on chromosome 15 was strongly associated with the level of response to alcohol.

This level of response includes physical reactions such as body swaying and subjective feelings described by terms such as “muddled”, “nauseated” or “sleepy”. Someone with a low level of response can consume greater amounts of alcohol before feeling the effects. A low level of response to alcohol is more common in people with a family history of alcoholism and is predictive of increased risk of alcohol use disorders.

The study’s findings were published in the Proceedings of the National Academy of Sciences, December 8. Raymond White, director of the Gallo Center and the paper’s senior author, said: “We know that the level of response to alcohol is heritable and think there are genetic factors behind 40 to 60 per cent of alcohol dependence, but until now the chromosomal locations of these factors have not been clear for the most common forms of alcohol use disorders.”

Several genes on chromosome 15, which has previously been linked with alcohol use disorders, could be responsible for the variation in response to alcohol, but the authors suspect that the nicotinic receptor gene CHRNA5 is responsible. Earlier studies have pointed to shared genetic factors behind both alcohol and nicotine dependence.

The research might lead to the development of a new generation of drugs to help fight addiction. It could also lead to a genetic test that could reveal susceptibility to alcohol abuse.

RiverOnline asked a small sample of Kingston University students whether they would take such a test if it were freely available. Just over 50% of respondents said that they would or probably would. When asked whether they would change their drinking behaviour if they learned that they had a genetic predisposition to alcohol abuse, more than 80% said that they would or probably would.

Some students were uncomfortable with the idea of a test for susceptibility to alcohol abuse. One suggested that it would cause more problems than it would solve: “People would start using it as an excuse, and say: ‘I’ve got the alcoholic gene; that’s why I’m like this.’ Another student, however, argued that it could be a used as an excuse for not drinking, by those who felt under pressure to do so.

Picture credit: USDEG/Phanie/Rex Features