The drinking habits of a romantic partner's friends are more likely to impact an adolescent's future drinking than are the behaviors of an adolescent's own friends or significant other, according to a new study in the October issue of the American Sociological Review.

"Dating someone whose friends are big drinkers is more likely to cause an adolescent to engage in dangerous drinking behaviors than are the drinking habits of the adolescent's own friends or romantic partner," said Derek Kreager, lead author of the study and an associate professor of crime, law, and justice at Pennsylvania State University. "This applies to both binge drinking and drinking frequency."

For example, the study found that the odds of an adolescent binge drinking if his or her partner's friends engage in heavy drinking is more than twice as high as the likelihood of an adolescent binge drinking if his or her friends or significant other drink heavily.

"The friends of a partner are likely to be very different from the adolescent and his or her friends and they might also be, at least a little, different from the partner," said Kreager, who coauthored the study with Dana A. Haynie, a sociology professor at Ohio State University. "Adolescents are motivated to be more like their partner's friends in an effort to strengthen their relationship with their partner."

Of course, the influence of a significant other's friends on an adolescent's drinking habits is not always negative. "If an adolescent is a drinker and he or she starts going out with someone whose friends predominately don't drink, you would find the same effect but in the opposite direction," Kreager said.

Relying on data from the National Longitudinal Study of Adolescent Health, a survey of U.S. adolescents enrolled in grades 7 through 12 in the 1994-1995 school year, the Kreager/Haynie study considers responses from 449 couples (898 students) in 1994, when they hadn't necessarily gotten together yet, and in 1996, after they had become a couple. Kreager and Haynie focus on heterosexual couples who were students during both waves of the survey.

In their study, the authors also found that before getting together, adolescent dating partners share few of the same friends and that an adolescent's friends are likely to be the same gender as he or she. "Couples often come from different friendship groups," said Kreager.

These results support the idea that the peer contexts of dating expose adolescents to new opportunities and norms that influence their own drinking behavior, while also increasing opposite-gender friendship ties and expanding early adolescent mixed-gender peer groups, according to the authors.

Still, Kreager said, it's important to note that although the drinking habits of a romantic partner's friends are more likely to impact an adolescent's future drinking than are the behaviors of an adolescent's own friends or significant other, the adolescent's friends and partner are likely to be influential nonetheless.

Interestingly, the research indicates limited gender differences in observed associations. "Consistent with prior literature, our findings indicate that girls are significantly less likely than their male partners to binge drink," Kreager said. "However, we find that connections with drinking friends, romantic partners, and friends-of partners have similar positive associations with the drinking habits of boys and girls. Moreover, our research suggests that, if anything, males are more susceptible to a significant other's influence than are girls."

In terms of policy implications, Kreager said, "The study demonstrates the need for educators and policymakers to more closely examine dating and the people dating puts adolescents in contact with when they consider interventions to address drinking behaviors, attitudes, and opportunities."