It’s a well-known fact that alcoholism runs in families, and for years scientists have been trying to single out which genes and which environments have the greatest impact on alcohol dependence. Recently, certain genes have been identified, but alcoholism is a complex condition that involves an interaction between genetic and environmental factors. One interaction that scientists in the Netherlands have tried to identify is how certain genes and lifestyles affect teens, and the likelihood of them becoming heavy drinkers before the age of 20.
“It has been estimated that 40 percent of adult alcoholics were heavy drinkers during adolescence,” notes Carmen S. Van der Zwaluw, author of the study. Like users of nicotine and other drugs, young alcohol drinkers are more likely to become addicted, and stay addicted, throughout their adult life than their peers who postpone drinking until a later age. Tackling the problem of alcoholism by focusing on teen drinking is therefore an effective strategy, both for the teens’ parents and researchers.
The Gene-Parenting Twin Study
Many studies have been done in the last two decades looking into the genetic predisposition for alcoholism and the role the environment plays in drinking habits. This study carried out in the Netherlands, however, takes this link a step further, investigating which genes are linked to which environmental triggers to influence alcohol abuse. Despite the complexity of the “nature vs. nurture” relationship, the study authors did make some notable discoveries.
Titled “Risky Alcohol Use in Adolescence: The Role of Genetics (DRD2, SLC6A4) and Coping Motives,” the study was authored by Carmen S. Van der Zwaluw and her colleagues at Radboud University in the Netherlands. They used six years of data on nearly 600 Dutch teens. During the course of the study, which took place in a series of waves, participants took a number of surveys to track their alcohol use and underwent DNA testing. Depending on their drinking habits, the participants were placed into one of three categories: light, moderate and heavy drinkers. By investigating the resulting data, the study researchers were able to piece together a relationship between genes and the environment. The study will be published in the March 2014 issue of the journal Alcoholism: Clinical & Experimental Research.
Genes That Influence Heavy Alcohol Use
A number of genes influence alcohol abuse and alcoholism, but this study looked at two in particular: the DRD2 gene, and the SLC6A4 gene.
One of the first genotypes ever discovered to be linked to alcohol, the D2 dopamine receptor may have an influence on a number of behavior patterns, and even some mental diseases. It was first shown to influence alcoholism in 1990. It comes as no surprise that this gene affects the dopamine receptor, which plays a large role in the brain’s reward-reinforcement pathway. Interestingly, this gene was found to influence binge drinking and alcohol dependence when the user drank as a coping mechanism for negative experiences or emotions.
The DRD2 gene has been linked with other disorders as well, including obesity, anorexia, gambling addiction and other drug addictions. Variants within the DRD2 genotype have also been implicated in Parkinson’s disease and Tourette syndrome.
A serotonin transporter gene, SLC6A4 is involved with emotions. Unlike the DRD2 gene, it doesn’t appear to be linked with drinking to cope with negative emotions, even though it influences a person’s emotional state. Instead, variants of this gene may be intertwined with the craving or urge to drink in dependent individuals.
Nature and Nurture Link to Teen Drinking
Finding a link between a genetic factor (DRD2) and an environmental factor (coping with negative emotions) is an exciting discovery, as this is the first time such a relationship has been shown. The implications of this discovery are also exciting. Teaching healthy emotional coping techniques, for example, could be especially beneficial for an at-risk teen with the DRD2 gene variant, potentially preventing alcohol abuse before it starts.
Because this study is the first of its kind to show a direct relationship between a gene and the environment, further studies are needed to see if the results can be replicated. The next step, according to Van der Zwaluw, is finding out “whether other genetic variants increase the risk for drinking problems,” and whether they too are linked to specific environmental triggers.
Regardless of the genes at play, every teen greatly benefits from a caring and involved parenting approach, and an environment that doesn’t encourage alcohol abuse. The most effective techniques to prevent alcohol abuse, however, may differ from genotype to genotype. It will be interesting to see if further studies can help parents determine the best way to approach alcohol with their teen, and perhaps even determine the best treatment options for teens who have already become dependent on alcohol.