title: Decomposing the components of friendship and friends' influence on adolescent drinking and smoking.
abstract: OBJECTIVE
  Friendship networks are an important source of peer influence. However, existing network studies vary in terms of how they operationalize friendship and friend's influence on adolescent substance use. This study uses social network analysis to characterize three types of friendship relations: (1) mutual or reciprocated, (2) directional, and (3) intimate friends. We then examine the relative effects of each friendship type on adolescent drinking and smoking behavior.
  
  
  METHODS
  Using a saturated sample from the Add Health data, a nationally representative sample of high school adolescents (N = 2,533 nested in 12 schools), we computed the level of exposure to drinking and smoking of friends using a network exposure model, and their association with individual drinking and smoking using fixed effect models.
  
  
  RESULTS
  Results indicated that the influence from mutual or reciprocated type of friendship relations is stronger on adolescent substance use than directional, especially for smoking. Regarding the directionality of directional type of friendship relations, adolescents are equally influenced by both nominating and nominated friends on their drinking and smoking behavior. Results for intimate friends friendship relations indicated that the influence from "best friends" was weaker than the one from non-"best friends," which indicates that the order of friend nomination may not matter as much as nomination reciprocation.
  
  
  CONCLUSIONS
  This study demonstrates that considering different features of friendship relationships is important in evaluating friends' influence on adolescent substance use. Related policy implications are discussed.
authors: Division of Health Promotion and Behavioral Sciences, School of Public Health, University of Texas at Houston, Houston, Texas 77030, USA. kayo.fujimoto@uth.tmc.edu
authors: Kayo
authors: K
authors: Fujimoto
authors: Thomas W
authors: TW
authors: Valente
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D000428:Alcohol Drinking / Q000453:epidemiology / Q000523:psychology*; D002648:Child; D003625:Data Collection; D005260:Female; D033062:Friends; D006801:Humans; D008297:Male; D012907:Smoking / Q000453:epidemiology / Q000523:psychology*; D012944:Social Support; D014481:United States / Q000453:epidemiology; D055815:Young Adult