The study, conducted by Danielle Dick, an assistant professor at Washington University, St. Louis and team looked at factors that may moderate the influence of peers. It found that gender, and gender of friends, can also affect this association.
"Several studies have found that peer drinking has more of an influence on an adolescent's drinking than his or her own parent's drinking," said Dick.
"We wanted to more closely examine the role that gender may also play, because even though there are profound differences that occur in development between girls and boys during adolescence, little is known about how influences on alcohol use may differ between the sexes during this developmental period," she said.
In the study, researchers used data from a population-based, longitudinal twin study of behavioural development and health-risk factors in which 4,700 individuals were examined.
The team analysed the association between friendship characteristics and alcohol use, testing for interaction with gender and gender of friends. They also used the twin structure of the data to examine the extent to which similarity in drinking behaviours between adolescents and their friends was due to shared genetic and/or environmental pathways.
The finding suggested that girls might be more influenced by their friends' drinking. "Our findings suggest that girls may be more susceptible to their friends' drinking, and that having opposite-sex friends who drink is also associated with increased drinking, for both sexes," Dick said.
"Furthermore, genetically based analyses suggest that the correlation between adolescent/friend drinking was largely attributable to shared environmental effects across genders. This suggests that the association between an adolescent's alcohol use and that of his or her peers is not merely a reflection of genetic influences on the adolescent's own alcohol use that cause them to select drinking peers," Dick added.
Dick cautioned parents to be very aware of their child's friends, as well as how they spend their time together. "This awareness is particularly important for girls, and when the friendship group consists of members of the opposite sex," Dick said.
The study is published in Alcoholism: Clinical & Experimental Research.