Drinking during adolescence has both short- and long-term negative health consequences. Prior research has shown that peer influence is one of the most important predictors of alcohol use in adolescence. This study used a high-school chat session to examine peer influence on adolescent drinking, finding that anti-alcohol norms seemed more influential than pro-alcohol norms, and that adolescents were more influenced by their high-status than low-status peers. Results will be published in the July 2012 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View. \"The key short-term consequences of drinking during adolescence are aggression, motor vehicle accidents, unprotected sex, alcohol poisoning, and vandalism,\" explained Hanneke A. Teunissen, a doctoral student at Radboud University Nijmegen as well as corresponding author for the study. \"The most important long-term consequences of alcohol use are an increased risk for developing substance use problems, brain damage, and other health-related problems later in life.\" \"The strong similarity between adolescents\' and their peers\' alcohol use is usually regarded as an indication that adolescents\' drinking behavior is influenced by peers,\" said Teunissen. \"However, previous studies have not always clarified whether the similarity between adolescents\' and peers\' alcohol use was due to peer influence or to the fact that adolescents select friends with similar drinking behavior like their own.\" Moreover, she added, prior research often assessed the effect of peer alcohol use by asking adolescents to report on their own and their peers\' alcohol use. \"It seems that people project their own behavior to others,\" she said, \"which means that adolescent perceptions of their peers\' alcohol use are biased and that reported similarities could lead to an overestimation of peer influence.\" Teunissen and her colleagues carried out their study in two parts. The first part consisted of class-questionnaire assessments of 532 adolescents (287 girls, 245 boys), 14 to 15 years old, at four high schools in The Netherlands. For the second part, 74 male adolescents were selected, on the basis of their reported experience with alcohol, to participate in a chat-room experiment. They were presented with pre-programmed pro- or anti-alcohol norms of \"peers\" or grade-mates; their willingness to adapt their drinking to the norms of these peers was tested; and their willingness to adapt their drinking based on the social status of these peers was also examined. \"We found that adolescents adapted their willingness to drink substantially to the alcohol norms of their peers,\" said Teunissen. \"Adolescents were more willing to drink when peers were holding pro-alcohol norms and adolescents were less willing to drink when peers were holding anti-alcohol norms. Adolescents were more influenced by popular than unpopular peers. Interestingly, the anti-alcohol norms of popular peers seemed most influential in that adolescents were less willing to drink when they were confronted with the anti-alcohol norms of popular peers. Additionally, the adolescents internalized these anti-alcohol norms, which means that they were still less willing to drink when the anti-alcohol norms of these peers were no longer presented to them.\" Teunissen noted that these findings help to focus on the positive effects that peers may have on adolescent behavior. \"We were not surprised that adolescents were affected by the anti-alcohol norms,\" she said. \"However, we were surprised that adolescents seemed to be more influenced by the anti-alcohol norms of popular peers than by the pro-alcohol norms.\" Teunissen said this study has three key messages for alcohol researchers. \"The first is clarification that peer influence can affect adolescents\' willingness to drink,\" she said. \"Second, popular peers seem to have a stronger influence on adolescents\' drinking behavior than unpopular peers; and third, popular peers may also have a protective effect on adolescents alcohol use.\" Teunissen added that these findings have particular resonance for both parents as well as clinicians who work with adolescents. \"They should be aware that adolescents are influenced by the alcohol norms of peers, especially by the norms of popular peers. Second, our finding that the anti-alcohol norms of popular peers seemed to be most influential can be an important contribution to the development of alcohol prevention and intervention programs. Exposing adolescents who drink heavily to anti-alcohol norms of popular peers may be an effective method to reduce alcohol consumption among these adolescents.\"