Elsevier

Annals of Epidemiology

Volume 21, Issue 9, September 2011, Pages 714-716
Annals of Epidemiology

Brief Communication
Adolescent Marijuana Use from 2002 to 2008: Higher in States with Medical Marijuana Laws, Cause Still Unclear

https://doi.org/10.1016/j.annepidem.2011.06.001Get rights and content

Purpose

Since 1996, 16 states have legalized marijuana use for medical purposes. The current study provides a scientific assessment of the association of medical marijuana laws (MML) and adolescent marijuana use using national data.

Method

State representative survey data on approximately 23,000 12–17 year olds were collected by the National Survey on Drug Use and Health annually from 2002–2008. Yearly state-specific estimates of prevalence of past-month marijuana use and perception of its riskiness were statistically tested for differences between states with and without MML by year and across years.

Results

States with MML had higher average adolescent marijuana use, 8.68% (95% CI: 7.95–9.42) and lower perception of riskiness, during the period 2002–2008 compared to states without MML, 6.94% (95% CI: 6.60–7.28%). In the eight states that passed MML since 2004, in the years prior to MML passage, there was already a higher prevalence of use and lower perceptions of risk in those states compared to states that have not passed MML.

Conclusions

While the most likely of several possible explanations for higher adolescent marijuana use and lower perceptions of risk in MML states cannot be determined from the current study, results clearly suggest the need for more empirically-based research on this topic.

Introduction

Between 1996 and 2011, 16 states passed laws legalizing use of marijuana for medical purposes when medically authorized (1). Due to the potential for serious short- and long-term consequences of marijuana use in adolescence 2, 3, 4, 5, 6, 7, prevention of adolescent marijuana initiation is a key NIDA strategy (8). Although the potential impact of MML has been much discussed in the popular press, formal scientific assessments of the relation between MML and adolescent marijuana use using national data are lacking. Using 2002–2008 data from the National Survey on Drug Use and Health (NSDUH), we compared the prevalence of marijuana use and perceptions of its riskiness among 12–17 year olds in states that have passed medical marijuana laws (MML) to states without such laws.

Section snippets

Methods

The NSDUH is administered to approximately 70,000 individuals annually and oversamples adolescents so that approximately one-third (n = 23,300) of the sample includes 12 to 17 year olds. Publicly available state-level estimates for NSDUH respondents aged 12–17 were compiled from 2002–2008 with 2008 being the most current results presently available (9). The NSDUH survey was initiated in 1999, but due to improvements in data collection procedures in 2002, prevalence rates before 2002 are not

Results

The overall prevalence of past-month marijuana use among 12–17 year olds averaged across all states and years was 7.50%. Figure 1 shows the prevalence by year for each state. The 16 states which passed MML (thick lines; solid after passage and dashed before passage) by 2011 had higher average use, 8.68% (95% CI: 7.95–9.42%), during the period 2002–2008 compared to the 34 states without MML, 6.94% (95% CI: 6.60–7.28%). Two states without MML but with high average use were New Hampshire (9.50%)

Discussion

Between 2002 and 2008, adolescent marijuana use was higher and perception of its riskiness lower in states with medical marijuana laws compared to states without such laws. There are several possible explanations for this observation. First, it is possible that states with higher marijuana use and lower perceptions of risk are more likely to enact MML. This explanation is supported in the current analysis by the observation that among states that eventually enacted MML, use was higher and

References (10)

  • C.Y. Chen et al.

    Early-onset drug use and risk for drug dependence problems

    Addict Behav

    (Mar 2009)
  • Procon.org. Medical Marijuana. http://medicalmarijuana.procon.org/view.resource.php?resourceID=000881. Accessed June 3,...
  • D.B. Kandel et al.

    Stages of progression in drug involvement from adolescence to adulthood: further evidence for the gateway theory

    J Stud Alcohol

    (Sep 1992)
  • P. Chatterji

    Illicit drug use and educational attainment

    Health Econ

    (May 2006)
  • M. Lemstra et al.

    A meta-analysis of marijuana and alcohol use by socio-economic status in adolescents aged 10–15 years

    Can J Public Health

    (May-Jun 2008)
There are more references available in the full text version of this article.

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