title: Teen Alcohol Use and Social Networks: The Contributions of Friend Influence and Friendship Selection.
abstract: BACKGROUND
  We evaluated the contributions of teen alcohol use to the formation and continuation of new and existing friendships while in turn estimating the influence of friend drinking on individuals' regular use and heavy drinking.
  
  
  METHODS
  Longitudinal network analysis was used to assess the mutual influences between teen drinking and social networks among adolescents in two large Add Health schools where full network data was collected three times. Friendship processes were disaggregated into the formation of new friendships and the continuation of existing friendships in a joint model isolating friendship selection and friend influences.
  
  
  RESULTS
  Friends have a modest influence on one another when selection is controlled. Selection is more complicated than prior studies suggest, and is only related to new friendships and not their duration in the largest school. Alcohol use predicts decreasing popularity in some cases, and popularity does not predict alcohol consumption.
  
  
  CONCLUSIONS
  Intervention efforts should continue pursuing strategies that mitigate negative peer influences. The development of socializing opportunities that facilitate relationship opportunities to select on healthy behaviors also appears promising. Future work preventing teen substance use should incorporate longitudinal network assessments to determine whether programs promote protective peer relationships in addition to how treatment effects diffuse through social networks.
authors.affiliation: The University of Nebraska-Lincoln, 737 Old father Hall, Lincoln, NE 68588-0324, USA.
authors.forename: Jacob E
authors.initials: JE
authors.lastname: Cheadle
authors.affiliation: Department of Health Promotion, Education, and Behavior, Arnold School of Public Health, 800 Sumter Street, Room 216, Columbia, SC 29208, USA.
authors.forename: Katrina M
authors.initials: KM
authors.lastname: Walsemann
authors.affiliation: The University of Nebraska-Lincoln, USA.
authors.forename: Bridget J
authors.initials: BJ
authors.lastname: Goosby