Peers, not genetics, make teens more likely to drink

When it comes to teens and alcohol abuse, peer pressure may trump genetics. Though some people carry a gene variant that decreases the likelihood that they'll develop an alcohol problem, it may not be enough to prevent younger people from drinking too much, especially in certain social settings around friends who consume alcohol in excess.

A new study published in the journal Alcoholism: Clinical & Experimental Research looks at the real-world impact a certain biomarker has on preventing teens from abusing alcohol. People who have this genetic variation, known as ADH1B, are more likely to experience unpleasant side effects of drinking -- headaches, nausea and vomiting -- and therefore are less likely to drink too much.

However, despite these consequences, many teens who carry the genetic variation still hit the bottle hard -- and researchers at Washington University School of Medicine in St. Louis say it's mostly due to the influence of close friends.

Emily Olfson, an MD/PhD student and lead author of the study, said that when it comes to teens, genetics don't matter when a party is heating up. "When in a high-risk environment -- that is, if they reported that 'most or all' of their best friends drank alcohol -- the gene's protective effect essentially disappeared," she said in a statement.

For the study, researchers at evaluated data from the Collaborative Study on Genetics and Alcoholism, a multi-center study that began in 1989. They interviewed people with a family history of alcohol abuse who also provided blood samples, and compared them with people who did not have a history of drinking or history of alcoholism in their family.

Approximately 40 percent of the sample reported that most or all of their best friends drink alcohol, and 6 percent had a copy of the protective ADH1B variant.

"Our final analyses show that adolescents with this ADH1B variant developed early drinking milestones (including at least one episode of alcohol intoxication and at least one symptom of alcohol use disorder) at approximately half the rate as adolescents without this protective ADH1B variant,"Olfson told CBS News.

Other research on teens and alcohol use has suggested that the earlier in life a young person begins drinking, the more likely they are to become an alcoholic in the future. But this study didn't find as strong a correlation. The drinking habits of friends were found to be the primary influence on teens who were otherwise less genetically inclined to drink.

Interestingly, the researchers note certain medications used to treat alcohol addiction involve the same pathways that are influenced by the ADH1B gene.

Alcohol abuse among adolescents is a serious and growing problem in the U.S. It's estimated that up to 78 percent of American teens have consumed alcohol by age 17, and 15 percent meet the criteria for alcohol abuse. In 2012, an estimated 855,000 adolescents aged 12 to 17 could be characterized as abusing alcohol, according the National Institute on Alcohol Abuse and Alcoholism, a division of the National Institutes of Health.

"From a public health perspective, this study provides a genetic argument in support of early social interventions to decrease affiliation with peer drinkers," write the authors in their study. "Specifically, these findings support the use of a screening tool for practitioners to identify at-risk youth developed by the National Institute on Alcohol Abuse and Alcoholism and the American Academy of Pediatrics, in which the first question addresses friends' drinking."