Recreational marijuana legalization

Evidence Rating  
Evidence rating: Insufficient Evidence

Strategies with this rating have limited research documenting effects. These strategies need further research, often with stronger designs, to confirm effects.

Health Factors  
Decision Makers
Date last updated

Policies that legalize marijuana for recreational use allow possession of a limited amount of marijuana for personal, non-medical use. Marijuana use is illegal in the United States at the federal level. Recreational use is prohibited in most states. Some states allow recreational use; allowances regarding home cultivation, maximum possession and purchase amounts, marketing and advertising restrictions, and taxes on marijuana products vary1, 2.

What could this strategy improve?

Expected Benefits

Our evidence rating is based on the likelihood of achieving these outcomes:

  • Reduced drug use

  • Reduced crime

Potential Benefits

Our evidence rating is not based on these outcomes, but these benefits may also be possible:

  • Reduced alcohol use

What does the research say about effectiveness?

There is insufficient evidence to determine whether legalizing recreational marijuana increases marijuana use1, 3, 4, 5 or affects overall crime rates6, 7, 8, 9. Available evidence suggests that legalizing marijuana for recreational use may decrease youth’s perceived risk1, 4, 10, 11, possibly increasing their use1, 4, 12. Legalization may also increase the risk of children’s unintentional toxic ingestions of marijuana products13, 14, 15 and increase marijuana-impaired driving and crashes1, 16, 17, 18. However, additional evidence is needed to confirm effects.

Following legalization in Colorado and Washington, the number of marijuana-related poison center calls and emergency room visits increased1; alcohol consumption did not appear to change6. Marijuana-related arrest rates decreased two years after Colorado legalized marijuana for recreational use; however, marijuana-related arrest rates among blacks remained substantially higher than rates among whites and Hispanics19.

Researchers suggest that legalizing marijuana for recreational use reduces its price3, 8, which could increase the likelihood of use3, 8 and lower the age of initiation20. Marijuana initiation before adulthood may increase the likelihood of dependence and related harms9, 21, 22; initiation over the age of 25 rarely results in dependence22.

Smoking marijuana may lead to respiratory problems, heart attacks, cancers, and cognitive impairment15, 23. Marijuana use may also increase the risk of psychotic and schizophrenic symptoms and may worsen schizophrenia, especially in genetically susceptible individuals and youth9, 22. The American Academy of Pediatrics (AAP) recommends routine screening and counseling for parents and youth about potential harms including damage to brain development, psychiatric illness, dropout, and suicide, particularly if recreational marijuana use is legal11, 24.

How could this strategy impact health disparities? This strategy is rated no impact on disparities likely.
Implementation Examples

As of October 2019, recreational marijuana is legal for adults age 21 or older in eleven states (Alaska, California, Colorado, Illinois, Massachusetts, Maine, Michigan, Nevada, Oregon, Vermont, and Washington) and Washington, D.C.25. These states also regulate licensing and location of recreational marijuana dispensaries; every state but Washington allows residents to cultivate a small amount of marijuana for personal use26. Detailed regulations on the maximum amount of marijuana possession, use, transfer, and home grow vary by state25.

As of August 2019, 33 states and Washington, D.C. allow residents to use medical marijuana27.

Implementation Resources

Addictions-Marijuana - Marijuana addiction.

NCSL-Marijuana - National Conference of State Legislatures (NCSL). Marijuana overview.


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1 Maxwell 2016 - Maxwell JC, Mendelson B. What do we know about the impact of the laws related to marijuana? Journal of Addiction Medicine. 2016;10(1):3-12.

2 Pacula 2017 - Pacula RL, Smart R. Medical marijuana and marijuana legalization. Annual Review of Clinical Psychology. 2017;13(1):397-419.

3 Hall 2016 - Hall W, Lynskey M. Evaluating the public health impacts of legalizing recreational cannabis use in the United States. Addiction. 2016;111(10):1764-1773.

4 Cerda 2017 - Cerdá M, Wall M, Feng T, et al. Association of state recreational marijuana laws with adolescent marijuana use. JAMA Pediatrics. 2017;171(2):142-149.

5 Mason 2016 - Mason WA, Fleming CB, Ringle JL, et al. Prevalence of marijuana and other substance use before and after Washington State’s change from legal medical marijuana to legal medical and nonmedical marijuana: Cohort comparisons in a sample of adolescents. Substance Abuse. 2016;37(2):330-335.

6 Guttmannova 2016 - Guttmannova K, Lee CM, Kilmer JR, et al. Impacts of changing marijuana policies on alcohol use in the United States. Alcoholism: Clinical & Experimental Research. 2016;40(1):33-46.

7 Maier 2017 - Maier SL, Mannes S, Koppenhofer EL. The implications of marijuana decriminalization and legalization on crime in the United States. Contemporary Drug Problems. 2017;44(2):125-146.

8 RAND-Kilmer 2012 - Kilmer B, Caulkins JP, Pacula RL. Marijuana legalization: What we know and what we don’t. In: RAND Congressional Briefing Series. Santa Monica: RAND Corporation; 2012.

9 Caulkins 2012 - Caulkins JP, Hawken A, Kilmer B, Kleiman MAR. Marijuana legalization: What everyone needs to know. New York: Oxford University Press; 2012.

10 Estoup 2016 - Estoup AC, Moise-Campbell C, Varma M, Stewart DG. The impact of marijuana legalization on adolescent use, consequences, and perceived risk. Substance Use & Misuse. 2016;51(14):1881-1887.

11 Ryan 2017 - Ryan SA, Ammerman SD, AAP Committee on Substance Use and Prevention. Counseling parents and teens about marijuana use in the era of legalization of marijuana. Pediatrics. 2017;139(3):e20164069.

12 Mason 2015 - Mason J, Wheeler W, Brown MJ. The economic burden of exposure to secondhand smoke for the child and adult never smokers residing in U.S. public housing. Public Health Reports. 2015;130(3):230-244.

13 Wang 2016 - Wang GS, Le Lait MC, Deakyne SJ, et al. Unintentional pediatric exposures to marijuana in Colorado, 2009-2015. JAMA Pediatrics. 2016;170(9):e160971.

14 RAND-Pacula 2017 - Pacula RL. Regulating medical marijuana markets: Insights from scientific evaluations of state experiments. Santa Monica: RAND Corporation; 2017.

15 Wilkinson 2016 - Wilkinson ST, Yarnell S, Radhakrishnan R, Ball SA, D’Souza DC. Marijuana legalization: Impact on physicians and public health. Annual Review of Medicine. 2016;67(1):453-466.

16 HLDI 2017 - Highway Loss Data Institute (HDLI). Recreational marijuana and collision claim frequencies. HLDI Bulletin. 2017;34(14).

17 AAA-Tefft 2016 - Tefft BC, Arnold LS, Grabowski JG. Prevalence of marijuana involvement in fatal crashes: Washington, 2010-2014 (May 2016). Washington, D.C.: AAA Foundation for Traffic Safety; 2016.

18 NHTSA-Ramirez 2016 - Ramirez A, Berning A, Carr K, et al. Marijuana, other drugs, and alcohol use by drivers in Washington State. Washington, D.C.: National Highway Traffic Safety Administration (NHTSA); 2016.

19 Males 2014 - Males M, Buchen L. Reforming marijuana laws: Which approach best reduces the harms of criminalization? A five-state analysis. San Francisco, CA: Center on Juvenile and Criminal Justice (CJCJ); 2014.

20 Van Ours 2012 - Van Ours JC. The long and winding road to cannabis legalization. Addiction. 2012;107(5):872-3.

21 Wilsey 2008 - Wilsey B, Marcotte T, Tsodikov A, et al. A randomized, placebo-controlled, crossover trial of cannabis cigarettes in neuropathic pain. Journal of Pain. 2008;9(6):506-21.

22 Bostwick 2012 - Bostwick JM. Blurred boundaries: The therapeutics and politics of medical marijuana. Mayo Clinic Proceedings. 2012;87(2):172-86.

23 Leung 2011 - Leung L. Cannabis and its derivatives: Review of medical use. Journal of the American Board of Family Medicine. 2011;24(4):452-62.

24 AAP-Ammerman 2015 - Ammerman S, Ryan S, Adelman WP. The impact of marijuana policies on youth: Clinical, research, and legal update. Pediatrics. American Academy of Pediatrics (AAP). 2015;135(3):e769-e785.

25 NCSL-Marijuana - National Conference of State Legislatures (NCSL). Marijuana overview.

26 WA-Marijuana use guide - Washington State Liquor and Cannabis Board. Marijuana use in Washington State: An adult consumer’s guide. 2016.

27 NCSL-MMLs - National Conference of State Legislatures (NCSL). State medical marijuana laws (MMLs).