title: A prospective study of marijuana use change and cessation among adolescents.
abstract: BACKGROUND
  With marijuana use increasing among American adolescents, better understanding of the factors associated with decreasing use and quitting can help inform cessation efforts. This study evaluates a range of neighborhood, family, peer network, and individual factors as predictors of marijuana use, change, and non-use over one year, and cessation over six years.
  
  
  METHODS
  Data come from adolescents in Waves I and II of the National Longitudinal Study of Adolescent Health (N=458, one-year sample), or Waves I and III (N=358, six-year sample), and reported using marijuana at least four times in the past month at Wave I.
  
  
  RESULTS
  Eighteen percent of adolescents stopped using marijuana after six years. Results suggest neighborhood context affects overall use level, whereas neighborhood context and friends were critical to cessation vs. continuation of use. Decrease in use were more likely among adolescents in disadvantaged or less cohesive neighborhoods, or who moved between waves. Non-use after one year was more likely among adolescents who did not move, had fewer marijuana-using friends, and did not exclusively have outside-of-school friends. Cessation at six years was more likely among adolescents in less disadvantaged and more cohesive neighborhoods, and for those with within-school friends.
  
  
  CONCLUSIONS
  Results highlight the importance of both objective and subjective neighborhood characteristics, as well as peer networks, on adolescent marijuana use. Factors associated with decreases in use appear distinct from those that predict quitting, suggesting that continuation vs. cessation is linked to peers as well as neighborhood context. Relocated and isolated individuals may face challenges with cessation.
authors.affiliation: RAND Corporation, 1776 Main Street, P.O. Box 3128, Santa Monica, CA, 90407-2138, United States. Electronic address: mpollard@rand.org.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Pollard
authors.affiliation: RAND Corporation, 1776 Main Street, P.O. Box 3128, Santa Monica, CA, 90407-2138, United States.
authors.forename: Joan S
authors.initials: JS
authors.lastname: Tucker
authors.affiliation: Keck School of Medicine, University of Southern California, 2001N. Soto Street, Los Angeles, CA, 90089-9239, United States.
authors.forename: Kayla
authors.initials: K
authors.lastname: de la Haye
authors.affiliation: RAND Corporation, 1776 Main Street, P.O. Box 3128, Santa Monica, CA, 90407-2138, United States.
authors.forename: Harold D
authors.initials: HD
authors.lastname: Green
authors.affiliation: RAND Corporation, 1776 Main Street, P.O. Box 3128, Santa Monica, CA, 90407-2138, United States.
authors.forename: David P
authors.initials: DP
authors.lastname: Kennedy
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D005260:Female; D033062:Friends / Q000523:psychology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology* / Q000523:psychology* / Q000628:therapy; D010379:Peer Group; D011446:Prospective Studies; D012111:Residence Characteristics; D012574:Schools
keywords: Adolescent; Cessation; Family; Marijuana; Neighborhood; Peer