Elsevier

Drug and Alcohol Dependence

Volume 140, 1 July 2014, Pages 145-155
Drug and Alcohol Dependence

Full length article
Temporal trends in marijuana attitudes, availability and use in Colorado compared to non-medical marijuana states: 2003–11

https://doi.org/10.1016/j.drugalcdep.2014.04.016Get rights and content

Abstract

Background

In 2009, policy changes were accompanied by a rapid increase in the number of medical marijuana cardholders in Colorado. Little published epidemiological work has tracked changes in the state around this time.

Methods

Using the National Survey on Drug Use and Health, we tested for temporal changes in marijuana attitudes and marijuana-use-related outcomes in Colorado (2003–11) and differences within-year between Colorado and thirty-four non-medical-marijuana states (NMMS). Using regression analyses, we further tested whether patterns seen in Colorado prior to (2006–8) and during (2009–11) marijuana commercialization differed from patterns in NMMS while controlling for demographics.

Results

Within Colorado those reporting “great-risk” to using marijuana 1–2 times/week dropped significantly in all age groups studied between 2007–8 and 2010–11 (e.g. from 45% to 31% among those 26 years and older; p = 0.0006). By 2010–11 past-year marijuana abuse/dependence had become more prevalent in Colorado for 12–17 year olds (5% in Colorado, 3% in NMMS; p = 0.03) and 18–25 year olds (9% vs. 5%; p = 0.02). Regressions demonstrated significantly greater reductions in perceived risk (12–17 year olds, p = 0.005; those 26 years and older, p = 0.01), and trend for difference in changes in availability among those 26 years and older and marijuana abuse/dependence among 12–17 year olds in Colorado compared to NMMS in more recent years (2009–11 vs. 2006–8).

Conclusions

Our results show that commercialization of marijuana in Colorado has been associated with lower risk perception. Evidence is suggestive for marijuana abuse/dependence. Analyses including subsequent years 2012+ once available, will help determine whether such changes represent momentary vs. sustained effects.

Introduction

Twenty states and the District of Columbia have legalized marijuana for certain qualifying medical conditions (ONDCP, 2013) and more than 280,000 individuals are registered for medical marijuana in the United States (Bowles, 2012). In 2012, Colorado and Washington state legalized possession of an ounce or less and recreational use of marijuana for those 21 years of age or older (Johnson, 2012, Gurman, 2012). Such ongoing policy shifts underscore the critical need to provide accurate scientific information to the public on the impact of marijuana medicalization/legalization; the potential impact of such legal and policy changes remains hotly debated.

Medical marijuana proponents cite the potential medical benefits of marijuana (Hecht, 2012), the increased tax revenue to states from the medical marijuana industry (Cooper, 2012), potential reduction in traffic fatalities due to alcohol (Anderson et al., 2013), potential reduction in criminal activities and criminal justice costs (Warf, 2005, Single, 1989) and the relative safety of cannabis as compared to other substances (SAFER, 2012). Opponents of medical marijuana legalization raise a multitude of concerns including: medical marijuana may lead to increasing adolescent marijuana use (Joffe, 2004, Joffe and Yancy, 2004, Svrakic et al., 2012); medical marijuana may be diverted to adolescents (Thurstone et al., 2011, Thurstone et al., 2013, Salomonsen-Sautel et al., 2012) or may lead to toxic ingestions by children (Wang et al., 2011, Wang et al., 2013); adolescent exposure to marijuana is associated with subsequent psychosis (Moore et al., 2007) and decline in IQ (Meier et al., 2012); and that medical marijuana may negatively impact public health by increasing prevalence of addiction, crimes and motor vehicle accidents (HDFC, 2012).

Only a handful of published findings document changes temporally associated with medical marijuana laws using epidemiological datasets. Using the second wave of National Epidemiologic Survey on Alcohol and Related Conditions collected in 2004–5, Cerdá et al. (2012) found that the prevalence of adult marijuana use, abuse and dependence was higher in states with medical marijuana laws compared to those without. Wall et al. (2011) using years 2002–8 of the National Survey on Drug Use and Health (NSDUH), showed a higher prevalence of adolescent marijuana use and lower perceptions of riskiness of use in states with medical marijuana laws compared to those without. Harper et al. (2012) replicated and extended the work of Wall et al. concluding that passage of medical marijuana laws had little impact on the prevalence of marijuana use or perceived risk; however, these results were based on findings from only 5 of the 16 states with existing medical marijuana laws which reduced its generalizability (Wall et al., 2012). Most recently, using the Youth Risk Behavior Survey for Montana, Rhode Island, Michigan and Delaware, Lynne-Landsman and colleagues examined whether medical marijuana laws were associated with changes in adolescent marijuana use; they concluded that such laws had not had a measurable impact on use patterns, at least in the first few years after enactment (i.e., 1–5 years; Lynne-Landsman et al., 2013).

As the scientific community begins to disentangle the effects of marijuana legalization/commercialization, certain US states present unique scientific opportunities. Colorado is a case in point. For example, Colorado not only maintains a medical marijuana registry but also posts summary information to the Colorado Department of Public Health and Environment (CDPHE) website, allowing monitoring of temporal trends. In many other states, it is difficult to assess the impact of medical marijuana laws and policy change because they do not maintain a medical marijuana registry (e.g., Washington), the state registry is voluntary (e.g., California), or information from the registry is not made available to the public (e.g., Hawaii; Bowles, 2012). Although in November, 2000, with the passage of Amendment 20 to the state constitution, Colorado legalized marijuana for medical purposes, review of the CDPHE records supports that from June, 2001 through January, 2009 only 6369 new patient applications were received by the CDPHE. In 2009 there was a confluence of three major policy decisions: (1) Attorney General Eric H. Holder Jr. announced an end to raids on distributors of medical marijuana in states where medical marijuana was legal (Johnston, 2009); (2) the Justice Department noted that federal resources should not be focused on prosecuting medical marijuana patients and caregivers who were operating in “clear and unambiguous compliance with existing state law” (Ogden, 2009); and (3) a Denver District Court ruling determined that a “caregiver” need only dispense marijuana to a registered patient and was not required to provide any additional care, which opened the way for large-scale retail medical marijuana centers (hereafter referred to as dispensaries; Elliott, 2009).

Following this, the Colorado medical marijuana industry experienced rapid growth. News reports quoting the acting Denver city treasurer indicated that by the beginning of 2010 there were nearly 400 medical marijuana dispensaries in Colorado (Channel 7 news, 2014), though the formal process of state licensing of dispensaries would not begin until that summer (Personal Communication, Julie Postlethwait, Medical Marijuana Enforcement Division). As of April 30th, 2013, there were 376 licensed dispensaries and 132 operating in Colorado under pending applications, bringing the total to 508 (personal communication Julie Postlethwait). During this same period the Colorado media attention to the issue of legal marijuana also rapidly increased (see Supplemental Figure 11). Although very few medical marijuana registry applications were received between 2000 and 2008, starting in 2009 the number of medical marijuana license holders in Colorado rapidly increased, reaching 116,198 individuals, or about 3% of Colorado's adult population, by the end of 2010 (refer to Supplemental Figure 22; CPDHE website; Census, 2010). Colorado's medical marijuana industry quickly matured, accumulating retail sales revenue of more than $219,000,000 between July, 2011 and June, 2012 (Colorado Department of Revenue, 2014). Instead of focusing on the point of legalization (pre-post passage of Amendment 20) when the medical marijuana industry in Colorado was relatively quiescent, here we focus on the potential impact of the rapid growth of the commercial medical marijuana industry in Colorado beginning in 2009.

In this study, we utilized the NSDUH to answer three questions: (1) How have marijuana attitudes and marijuana-use-related outcomes changed across time from 2003–4 to 2010–11 within Colorado? (2) Considering these same variables, did Colorado differ from 34 states without medical marijuana laws in years 2003–4, 2005–6, 2007–8, 2009–10 and 2010–11? (3) Do trends in Colorado between 2006–8 and 2009–11 differ from those seen in non-medical marijuana states (NMMS) for the same time periods while adjusting for demographic differences?

Section snippets

Methods

The Colorado Multiple Institutional Review Board approved the study as an exempt protocol.

Results

Nine tables are also included as Supplemental Materials, in addition to three tables.4 They provide details on prevalence estimates, standard errors, and p-values. Data from those detailed tables are summarized in Fig. 1, Fig. 2. For Fig. 1, Fig. 2, the vertical axis is percentage; the horizontal axis shows combined two year sequences. Each blue line (diamond markers)

Discussion

We present detailed information on temporal trends within Colorado for multiple marijuana-related variables, and test for Colorado vs. NMMS differences within time (e.g., years 2003–4, 2005–6, etc.). Our findings can be divided into those that represent: (1) trends associated temporally with changes in 2009; (2) differences between Colorado and NMMS in 2010–11; (3) variables without significant change pre-post early 2009; and (4) trends in Colorado pre-post early 2009 that deviate from patterns

Grant support

Dr. Sakai is supported by R01DA031761, P60DA011015, R01DA029258 and the Kane Family Foundation; Dr. Price is supported by W81XWH-11-2-0108, T32DA007313 and Barnes-Jewish Hospital Foundation. Dr. Balan is supported by T32DA007313, Dr. Thurstone is supported by 5R01 DA031816 and Dr. Salomonsen-Sautel was supported by T32AA007464.

Author contributions

Drs. Sakai, Schuermeyer and Salomonsen-Sautel drafted the original study aims and analytic approach. Drs. Price, Balan, Thurstone and Min made important suggested revisions. Dr. Schuermeyer wrote the first draft of the manuscript, while Dr. Sakai provided the first revision. All authors subsequently provided critical revisions of important intellectual content, which Dr. Sakai incorporated into the final manuscript. All authors approved of the submitted draft.

Conflicts of interest

Dr. Sakai received reimbursement in 2012 for completing a policy review for the WellPoint Office of Medical Policy & Technology Assessment (OMPTA), WellPoint, Inc., Thousand Oaks, CA. He also serves as a board member of the ARTS (Addiction Research and Treatment Services) Foundation. All other authors report no conflicts of interest.

Acknowledgements

We gratefully acknowledge Art Hughes, SAMHSA, Center for Behavioral Health Statistics and Quality, for his assistance in the completion of the study data analyses. Librarian Ellen Metter aided in identifying the most appropriate database and discussed search strategies for media sources described in Supplemental Figure 1. We also thank Julie D. Postlethwait, Public Information Officer, Medical Marijuana Enforcement Division, for providing data on medical marijuana dispensary licensing in

References (45)

  • J.G. Bachman et al.

    Explaining the recent decline in cocaine use among young adults: further evidence that perceived risks and disapproval lead to reduced drug use

    J. Health Soc. Behav.

    (1990)
  • D.W. Bowles

    Persons registered for medical marijuana in the United States

    J. Palliat. Med.

    (2012)
  • CDPHE (Colorado Department of Public Health and Environment), 2012....
  • Census, 2010. http://quickfacts.census.gov/qfd/states/08000.html. Accessed July 10,...
  • Channel 7 news, 2010. Denver Pot Dispensaries: 390; Colo. Starbucks: 208 Mile High City Called ‘America's Cannabis...
  • Colorado Department of Revenue, 2014....
  • Cooper, M., 2012. New York Times: Cities Turn to a Crop for Cash....
  • Elliott, D., 2009. Huffington post: Medical Marijuana in Colorado: Judge Voids Board Of Health Decision....
  • EMCDDA, 2012. Prevalence of Daily Cannabis Use in the European Union and Norway. Publication Office of the European...
  • Grim, R., 2011. Huffington Post: Medical Marijuana Memo: DOJ Cracks Down On Pot Shops....
  • Gurman, S., 2012. Denver Post: Coloradans say yes to recreational use of marijuana....
  • HDFC (Health and Drug Free Colorado), 2012....
  • Cited by (216)

    • Impact of Cannabis Legalization on Adolescent Cannabis Use

      2023, Psychiatric Clinics of North America
    • Impact of Cannabis Legalization on Adolescent Cannabis Use

      2023, Child and Adolescent Psychiatric Clinics of North America
    View all citing articles on Scopus

    Supplementary material can be found by accessing the online version of this paper at http://dx.doi.org and by entering doi:….

    View full text