Fundamental research on the triggers for alcohol consumption finds the answer could lie in our genes, with the amount of beer and wine people consume related to differences in genetic make-up.
Researchers at the University of Bristol in the UK, together with Oxford University colleagues, suggest genes could influence the risk of alcohol dependence.
"Understanding genetic influences on behaviour is important if we are to understand why some people are more likely to become addicted than others," said lead researcher Dr Marcus Munafò, at Bristol University.
In a large scale study the UK scientists analysed data from almost a thousand people who gave detailed information on their drinking habits. The research focused on a key gene that controls chemical signalling in the brain.
Different versions of this gene may affect the balance and effect of signalling molecules and in turn help to shape individual drinking habits, they say.
Scientists do not know precisely why particular genetic variants may influence behaviour, but they do have a few clues.
They found that one particular genetic variant - a version of the dopamine D2 receptor gene (DRD2) - was strongly associated with alcohol consumption.
The DRD2 gene appears to influence the 'high' that people derive from drugs such as alcohol. People without this variant might derive less pleasure from alcohol, and may therefore drink less.
Full findings are published in the March issue of The Pharmacogenomics Journal.