title: Trends in use of marijuana and attitudes toward marijuana among youth before and after decriminalization: the case of California 2007-2013.
abstract: BACKGROUND
  This analysis examines decriminalization as a risk factor for future increases in youth marijuana acceptance and use. Specifically, we examine marijuana-related behaviors and attitudes of 8th, 10th, and 12th graders in California as compared to other U.S. states during the years before and after California passed legislation in 2010 to decriminalize marijuana.
  
  
  METHODS
  Data come from Monitoring the Future, an annual, nationally representative survey of 8th, 10th, and 12th grade students.
  
  
  RESULTS
  In 2012 and afterwards California 12th graders as compared to their peers in other states became (a) 25% more likely to have used marijuana in the past 30 days, (b) 20% less likely to perceive regular marijuana use as a great health risk, (c) 20% less likely to strongly disapprove of regular marijuana use, and (d) about 60% more likely to expect to be using marijuana five years in the future. Analysis of 10th graders raises the possibility that the findings among 12th graders may reflect a cohort effect that was set into place two years earlier.
  
  
  CONCLUSIONS
  These results provide empirical evidence to support concerns that decriminalization may be a risk factor for future increases in youth marijuana use and acceptance.
authors: University of Michigan, 426 Thompson Street, Ann Arbor, MI 48104, USA. Electronic address: ramiech@umich.edu.
authors: Richard A
authors: RA
authors: Miech
authors: University of Michigan, 426 Thompson Street, Ann Arbor, MI 48104, USA.
authors: Lloyd
authors: L
authors: Johnston
authors: University of Michigan, 426 Thompson Street, Ann Arbor, MI 48104, USA.
authors: Patrick M
authors: PM
authors: O'Malley
authors: University of Michigan, 426 Thompson Street, Ann Arbor, MI 48104, USA.
authors: Jerald G
authors: JG
authors: Bachman
authors: University of Michigan, 426 Thompson Street, Ann Arbor, MI 48104, USA.
authors: John
authors: J
authors: Schulenberg
authors: University of Michigan, 426 Thompson Street, Ann Arbor, MI 48104, USA.
authors: Megan E
authors: ME
authors: Patrick
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D000367:Age Factors; D001290:Attitude; D016739:Behavior, Addictive; D002140:California; D003415:Crime / Q000331:legislation & jurisprudence* / Q000639:trends; D004335:Drug and Narcotic Control / Q000331:legislation & jurisprudence* / Q000639:trends; D006801:Humans; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology; D008385:Marijuana Smoking / Q000453:epidemiology* / Q000331:legislation & jurisprudence / Q000523:psychology / Q000639:trends; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013997:Time Factors
keywords: Adolescent; Decriminalization; Marijuana