title: Longitudinal Relationships Among Perceived Injunctive and Descriptive Norms and Marijuana Use.
abstract: The current study uses longitudinal data to examine the relative influence of perceived descriptive and injunctive norms for proximal and distal referents on marijuana use.
  
  
  
  Participants were 740 undergraduate students (67% female) who completed web-based surveys at two time points 12 months apart. Time 1 measures included reports of marijuana use, approval, perceived descriptive norms, and perceived injunctive norms for the typical student, close friends, and parents. At Time 2, students reported on their marijuana use.
  
  
  
  Results of a path analysis suggest that, after we controlled for Time 1 marijuana use, greater perceived friend approval indirectly predicted Time 2 marijuana use as mediated by personal approval. Greater perceived parental approval was both indirectly and directly associated with greater marijuana use at follow-up. Perceived typical-student descriptive norms were neither directly nor indirectly related to Time 2 marijuana use.
  
  
  
  The findings support the role of proximal injunctive norms in predicting college student marijuana use up to 12 months later. The results indicate the potential importance of developing normative interventions that incorporate the social influences of proximal referents.
authors.affiliation: Department of Psychology & Health, Medicine, & Society Program, Lehigh University, Bethlehem, Pennsylvania.
authors.forename: Lucy E
authors.initials: LE
authors.lastname: Napper
authors.affiliation: Center for Alcohol and Addiction Studies, Brown University, Providence, Rhode Island.
authors.forename: Shannon R
authors.initials: SR
authors.lastname: Kenney
authors.affiliation: Department of Psychology, University of Southern California, Los Angeles, California.
authors.forename: Justin F
authors.initials: JF
authors.lastname: Hummer
authors.affiliation: Department of Psychology & Health, Medicine, & Society Program, Lehigh University, Bethlehem, Pennsylvania.
authors.forename: Sara
authors.initials: S
authors.lastname: Fiorot
authors.affiliation: Department of Psychology, Loyola Marymount University, Los Angeles, California.
authors.forename: Joseph W
authors.initials: JW
authors.lastname: LaBrie
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology*; D010465:Perception; D066262:Social Norms; D013334:Students; D014495:Universities; D055815:Young Adult