Scientists could soon be able to predict whether teenage boys are likely to become heavy drinkers by looking at whether they carry a particular variant of a gene linked to thrill-seeking behaviour, a study suggests.
The researchers said the findings will help them to develop better ways of identifying children who are at risk of misusing alcohol so that they can be encouraged to avoid binge drinking in later life.
A study involving hundreds of teenagers found that a gene called RASGRF-2 plays an important role in predisposing some individuals to heavy or frequent drinking. The same gene is also 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, explaining why some people are more prone to the effects of heavy drinking and alcohol abuse.
“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 RASGRF-2 gene 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 at various medical centres around Britain and the rest of Europe 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,” he said.
The research, which is part of a pan-European study known as the Imagen Consortium, followed the 14-year-old boys until they reached the age of 16, when they had begun to drink on a regular basis.
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. In other words, the gene variation can be used to predict whether an individual is likely to become a heavy drinker.
“Identifying risk factors for early alcohol abuse is important in designing prevention and treatment interventions for alcohol addiction,” Professor Schumann said.
Brain scans carried out on the boys revealed that those who were 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 that 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.
“There are a multitude of genes that are contributing to addiction and in this study we’ve found one that appears to be involved in responding to the sense of anticipation of a reward,” Dr Conrod said.
“Drinking behaviour is highly genetically determined and this is one factor that is significantly related to drinking behaviour which is associated with reward. It is about the anticipating of a reward, rather than the receiving of a reward that’s important here,” she said.