Association Between Recreational Marijuana Legalization in the United States and Changes in Marijuana Use and Cannabis Use Disorder From 2008 to 2016

Abstract

IMPORTANCELittle is known about changes in marijuana use and cannabis use disorder (CUD) after recreational marijuana legalization (RML).OBJECTIVES To examine the associations between RML enactment and changes in marijuana use, frequent use, and CUD in the United States from 2008 to 2016. DESIGN, SETTING, AND PARTICIPANTSThis survey study used repeated cross-sectional survey data from the National Survey on Drug Use and Health (2008-2016) conducted in the United States among participants in the age groups of 12 to 17, 18 to 25, and 26 years or older.INTERVENTIONS Multilevel logistic regression models were fit to obtain estimates of before-vs-after changes in marijuana use among respondents in states enacting RML compared to changes in other states.MAIN OUTCOMES AND MEASURES Self-reported past-month marijuana use, past-month frequent marijuana use, past-month frequent use among past-month users, past-year CUD, and past-year CUD among past-year users. RESULTSThe study included 505 796 respondents consisting of 51.51% females and 77.24% participants 26 years or older. Among the total, 65.43% were white, 11.90% black, 15.36% Hispanic, and 7.31% of other race/ethnicity. Among respondents aged 12 to 17 years, past-year CUD increased from 2.18% to 2.72% after RML enactment, a 25% higher increase than that for the same age group in states that did not enact RML (odds ratio [OR], 1.25; 95% CI, 1.01-1.55). Among past-year marijuana users in this age group, CUD increased from 22.80% to 27.20% (OR, 1.27; 95% CI, 1.01-1.59). Unmeasured confounders would need to be more prevalent in RML states and increase the risk of cannabis use by 1.08 to 1.11 times to explain observed results, indicating results that are sensitive to omitted variables. No associations were found among the respondents aged 18 to 25 years. Among respondents 26 years or older, past-month marijuana use after RML enactment increased from 5.65% to 7.10% (OR, 1.28; 95% CI, 1.16-1.40), past-month frequent use from 2.13% to 2.62% (OR, 1.24; 95% CI, 1.08-1.41), and past-year CUD from 0.90% to 1.23% (OR, 1.36; 95% CI, 1.08-1.71); these results were more robust to unmeasured confounding. Among marijuana users in this age group, past-month frequent marijuana use and past-year CUD did not increase after RML enactment.CONCLUSIONS AND RELEVANCE This study's findings suggest that although marijuana legalization advanced social justice goals, the small post-RML increase in risk for CUD among respondents aged 12 to 17 years and increased frequent use and CUD among adults 26 years or older in this study are a potential public health concern. To undertake prevention efforts, further studies are warranted to assess how these increases occur and to identify subpopulations that may be especially vulnerable.

Assessing the public health impacts of legalizing recreational cannabis use: the US experience

“…They were cautious in interpreting the former, because they estimated that the small increases could be due to unmeasured confounders. This was a less plausible explanation for similar increases observed in regular cannabis use and cannabis use disorders among adults 26 years and older 81 .…”

“…Household survey data suggest that lower cannabis prices have increased the frequency of use among adult cannabis users in US states that have legalized recreational cannabis 78,81,82 . Surveys in Colorado and Washington State have found mixed evidence on the impacts of cannabis legalization on adolescent cannabis use.…”

“…Cerdá et al 81 recently compared trends in regular past 30 day cannabis use and cannabis use disorders among adolescents and young adults in US states that have and have not legalized recreational cannabis use, using data from the US drug household survey, the National Survey on Drug Use and Health. They found suggestive evidence of a small increase in these outcomes among 12‐17 year olds, but did not find any similar effects among those aged 18‐25 years.…”

Cannabis et neurodéveloppement

“…Plus précisément, les trois-quarts des troubles psychiatriques débutent avant l'âge de 25 ans, avec un pic entre 12 et 30 ans, reflétant la vulnérabilité associée à cette période critique de l'adolescence. Notons que la modification de la législation aux USA a entraîné une augmentation de la prévalence des troubles de la consommation du cannabis particulièrement chez les jeunes de 12-17 ans [41]. L'induction d'un syndrome amotivationnel est très fréquente lors d'une consommation chronique.…”

To legalize or not to legalize cannabis, that is the question!

“…Indeed, data from a large and nationally representative US survey 4 quoted by the authors, based on state‐level estimates spanning 2008‐2016, tentatively suggest trends of increase in cannabis use among young adolescents (12‐17 years old) in those states where recreational cannabis use is legal.…”