Gene clue to social drinking habits

A person's drinking habits, and possibly their tendency to become addicted to alcohol, may be influenced by differences in a key brain chemical gene, say UK researchers. Scientists based at the Universities of Bristol and Oxford found that people with a particular version of the DRD2 gene drink less alcohol, confirming an earlier Finnish study. The gene variant's effect was stronger in men than in women, say the team, who published their findings in the Pharmacogenomics Journal.

The researchers studied the DRD2 gene type of nearly 1000 people, who all gave detailed information on their drinking habits. 'Our study suggests that there's a genetic basis to certain kinds of behaviour, including alcohol consumption', said team leader Marcus Munafo, adding that such differences 'may be important in influencing whether people are at an increased risk of alcohol dependence'. Understanding genetic influences is important for understanding why some more people are more likely to become addicted to alcohol, the scientists say.

Previous studies have shown that a tendency to become addicted to alcohol is influenced by genes, as well as non-genetic factors such as upbringing. Alcohol and other drugs are thought to exert their effects by triggering the brain's 'reward' chemical dopamine, produced naturally in response to food and sex. The DRD2 gene makes a receptor protein that sticks to dopamine, enabling brain cells to receive 'pleasure' messages. People with a particular version of DRD2 may be less responsive to the alcohol-triggered effects of dopamine, and so will drink less, whereas those with a different version of this gene may get more of a 'high' from alcohol, and so will drink more.

Another version of the DRD2 gene have been implicated in smoking behaviour, and the effectiveness of nicotine replacement therapies, a team based at the University of Oxford reported last year.