New research helps explain why some teenagers are more prone to drinking alcohol than others. The study, led by a researcher at King’s College London’s Institute of Psychiatry (IoP), discovered a genetic link in teenage alcohol abuse.
Alcohol and other addictive drugs activate the dopamine system in the brain which is responsible for feelings of pleasure and reward, said the researchers, who note that recent studies from the college found that the RASGRF2 gene is a risk gene for alcohol abuse.
“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,” said Gunter Schumann, M.D., Ph.D., lead author of the study.
“We now understand the chain of action: How our genes shape this function in our brains and how that, in turn, leads to human 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.”
The study initially looked at mice without the RASGRF2 gene to see how they reacted to alcohol.
The researchers found that the absence of the RASGRF-2 gene was linked to a significant reduction in alcohol-seeking activity.
Upon intake of alcohol, the absence of the RASGRF-2 impaired the activity of dopamine-releasing neurons in a region of the brain called the ventral tegmental area (VTA) and prevented the brain from releasing dopamine and, therefore, any sense of reward.
The research team then analyzed the brain scans of 663 14-year-old boys who had not been exposed to significant amounts of alcohol.
They found that boys with genetic variations to the RASGRF2 gene had higher activation of the ventral striatum area of the brain, which is closely linked to the VTA and involved in dopamine release, when anticipating a reward in a cognitive task.
This suggests that individuals with a genetic variation on the RASGRF-2 gene release more dopamine when anticipating a reward, which means they derive more pleasure from the experience.
The researchers then analyzed the drinking behavior from the same group of boys at 16 years old, when many had already begun drinking frequently. They found that the boys with the variation on the RASGRF-2 gene drank more frequently at the age of 16 than those with no variation on the gene.
“Identifying risk factors for early alcohol abuse is important in designing prevention and treatment interventions for alcohol addiction,” Schumann noted.
The study was published in Proceedings of National Academy of Sciences (PNAS).
Source: King’s College London