Some teens may be primed to binge drink because they have a version of a gene that makes alcohol stimulate stronger feelings of pleasure and reward, according to new research from the UK that provides the most detailed understanding so far of the underlying brain processes involved.
The study, led by King’s College London’s Institute of Psychiatry (IoP) is published online this week in the Proceedings of National Academy of Sciences, PNAS.
Teenage drinking is common in England, where around 60% of youngsters aged 11 to 15 report drinking alcohol. That figure has not changed much in the last two decades.
But what has become more common in this age group is binge drinking: consuming large amounts of alcohol in a short space of time.
Studies show teens’s alcohol consumption has gone up from 6 units a week in 1994 to 13 in 2007.
The authors note that every year in the UK, around 5,000 teenagers are hospitalized because of drink.
Apart from the obvious problems such as increased anti-social and risk-taking behavior (for example drunk driving and unsafe sex), alcohol abuse in teenagers has also been linked to poor brain development and long term health problems.
Addictive substances like alcohol stimulate the release of the brain chemical dopamine, which creates feelings of pleasure and reward.
Several genes have been linked to risk for alcohol abuse, including RASGRF-2, identified in recent studies from King’s IoP.
But this latest study is the first to suggest the underlying mechanism through which the gene stimulates the brain to release dopamine.
Gunter Schumann, a professor at King’s IoP and lead author of the study, says in a press statement:
“People seek out situations which fulfill their sense of reward and make them happy, so if your brain is wired to find alcohol rewarding, you will seek it out.”
Schumann and colleagues believe they now understand the sequence of events through which genes shape the effect of alcohol in the brain to influence behavior.
“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. 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,” Schumann explains.
He and his colleagues found mice without the RASGRF-2 gene did not seek out alcohol. And when they did have alcohol, the lack of the gene stopped dopamine being release in a region of the brain called ventral tegmental area (VTA), so there was no sense of reward.
Using brain scans, the researchers then analyzed brain activity in 663 boys aged 14 who had not yet drunk much alcohol. They found the boys who carried the higher risk version of the RASGRF-2 gene had more activity in the ventral striatum area of the brain when anticipating reward in a mental challenge. This part of the brain is closely linked to the VTA and is involved in the release of dopamine.
The researchers suggest this showed the boys with the higher risk version of the gene released more dopamine when anticipating reward, and thus felt more pleasure.
To test the link with alcohol, the researchers then contacted the same group of boys again when they were 16. By this time, many of them were already frequent alcohol drinkers.
They found boys with the risky version of RASGRF-2 drank alcohol more often than boys who did not have it.
Schumann says further research should now be done to look at the effects of alcohol in the brains of teenage girls, according to a BBC report of the study.
In 2011, researchers from the University of California, San Diego and Stanford University, suggested binge drinking damages teenage girls’ brains more than boys’.
Schumann says it is important to find risk factors for alcohol abuse early to ensure successful prevention and treatment.
Funds from the European Union (EU) and the UK Medical Research Council (MRC) paid for the study, which is part of the IMAGEN Consortium, where scientists in the EU are investigating reinforcement behavior and mental health in young people with the help of 2,000 teenage volunteers in Ireland, England, France, and Germany.
Written by Catharine Paddock PhD