London - Scientists could soon be able to predict whether teenage boys are likely to become heavy drinkers by looking at whether they carry a variant of a gene linked to thrill-seeking behaviour.
The researchers said the findings will help them to develop better ways of identifying children who are at risk of misusing alcohol in later life.
A study involving hundreds of teenagers found that a gene plays an important role in predisposing some individuals to frequent drinking. The same gene is known to be involved with “reward anticipation” in the brain.
Scientists believe that the research will lead to a greater understanding of how alcohol affects people in different ways depending on their genetic makeup. “People seek out situations which fulfil their sense of reward and make them happy, so if your brain is wired to find alcohol rewarding, you will seek it out,” said Professor Gunter Schumann of the Institute of Psychiatry at King's College London.
“We now understand the chain of action - how our genes shape this function in our brains and how that, in turn, leads to human behaviour,” said Professor Schumann, a lead author of the study published in the Proceedings of the National Academy of Sciences.
Previous research on laboratory mice has shown that the gene, called RASGRF-2, influences whether animals seek out alcohol, and that this behaviour is tied in with the way the brain anticipates a sense of reward, which is controlled by the release of dopamine, a neurotransmitter released between nerve cells.
The latest study investigated DNA variations of the RASGRF-2 gene in 663 boys aged 14, who underwent brain scans to monitor the part of the brain known to be involved in anticipating a sense of reward.
“We found that the RASGRF-2 gene plays a crucial role in controlling how alcohol stimulates the brain to release dopamine, and hence trigger the feeling of reward,” Professor Schumann said. “So, if people have a genetic variation of the RASGRF-2 gene, alcohol gives them a stronger sense of reward, making them more likely to be heavy drinkers.”
The research, which is part of a pan-European study known as the Imagen Consortium, followed the 14-year-old boys until they reached 16. Those 16-year-olds with the variation of the RASGRF-2 gene drank more frequently than their contemporaries who did not have the gene variation.
Brain scans carried out on the boys revealed that those carrying the gene variation were more likely to show increased activity in the ventral striatum area of the brain, which is closely associated with the release of dopamine and the sense of anticipating a reward.
Patricia Conrod, of the University of Montreal, said the findings show how a person's genetic makeup can be connected to brain activity and the sort of thrill-seeking behaviour that can lead to drug or alcohol addiction.
THE STUDY: TEEN TENDENCIES
Interviewing underage teenage boys about drinking needed the approval of local hospital ethical committees overseeing the research at the eight centres in the UK, Ireland, France and Germany. The boys were recruited from local high schools and their parents, who had to give approval, were not allowed to see the boys' answers to questionnaires to assess their attitudes to alcohol. - The Independent