title: Medical marijuana laws in 50 states: investigating the relationship between state legalization of medical marijuana and marijuana use, abuse and dependence.
abstract: BACKGROUND
  Marijuana is the most frequently used illicit substance in the United States. Little is known of the role that macro-level factors, including community norms and laws related to substance use, play in determining marijuana use, abuse and dependence. We tested the relationship between state-level legalization of medical marijuana and marijuana use, abuse, and dependence.
  
  
  METHODS
  We used the second wave of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a national survey of adults aged 18+ (n=34,653). Selected analyses were replicated using the National Survey on Drug Use and Health (NSDUH), a yearly survey of ∼68,000 individuals aged 12+. We measured past-year cannabis use and DSM-IV abuse/dependence.
  
  
  RESULTS
  In NESARC, residents of states with medical marijuana laws had higher odds of marijuana use (OR: 1.92; 95% CI: 1.49-2.47) and marijuana abuse/dependence (OR: 1.81; 95% CI: 1.22-2.67) than residents of states without such laws. Marijuana abuse/dependence was not more prevalent among marijuana users in these states (OR: 1.03; 95% CI: 0.67-1.60), suggesting that the higher risk for marijuana abuse/dependence in these states was accounted for by higher rates of use. In NSDUH, states that legalized medical marijuana also had higher rates of marijuana use.
  
  
  CONCLUSIONS
  States that legalized medical marijuana had higher rates of marijuana use. Future research needs to examine whether the association is causal, or is due to an underlying common cause, such as community norms supportive of the legalization of medical marijuana and of marijuana use.
authors.affiliation: Department of Epidemiology, Mailman School of Public Health, Columbia University, 722 W168th St., New York, NY 10032-3727, United States. mc3226@columbia.edu
authors.forename: Magdalena
authors.initials: M
authors.lastname: Cerdá
authors.forename: Melanie
authors.initials: M
authors.lastname: Wall
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Keyes
authors.forename: Sandro
authors.initials: S
authors.lastname: Galea
authors.forename: Deborah
authors.initials: D
authors.lastname: Hasin
mesh_terms: D000328:Adult; D002188:Cannabis; D004335:Drug and Narcotic Control / Q000331:legislation & jurisprudence*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology*; D008875:Middle Aged; D014481:United States; D055815:Young Adult
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