Medical marijuana legalization
Policies that legalize marijuana for medical purposes remove civil or criminal penalties and permit the sale and use of medical marijuana products for eligible patients1, 2, 3. Marijuana use is illegal in the United States at the federal level. Some states allow medical marijuana use for eligible patients; requirements and restrictions regarding patient authorization and registration, caregiver role and registration, medical conditions, home cultivation, and dispensary permission vary by state1.
What could this strategy improve?
Expected Benefits
Our evidence rating is based on the likelihood of achieving these outcomes:
Improved health outcomes
Improved mental health
Reduced opioid-related mortality
Reduced opioid prescribing
Reduced alcohol use
Potential Benefits
Our evidence rating is not based on these outcomes, but these benefits may also be possible:
Reduced crime
What does the research say about effectiveness?
There is mixed evidence about the health benefits and risks of legalizing marijuana for medical use. Medical marijuana has been shown to effectively treat or provide symptom relief for certain conditions4, 5, 6, 7, 8. More research is needed to determine the effects of legalizing medical marijuana on long-term health, safety, and socioeconomic outcomes9.
Medical marijuana laws (MMLs) increase marijuana use among adults and have no significant impact on adolescent and young adult marijuana use, with some studies finding small decreases in youth marijuana use10, 11, 12, 13, 14. MMLs are associated with increased risk of unintentional toxic ingestions of marijuana products among adults, adolescents, and children15, 16. MMLs may be associated with increases in marijuana use among women who are pregnant17.
MMLs may have positive impacts on mental health outcomes, such as decreased rates of suicide11 and fewer reported poor mental health days18. However, one study finds that MMLs are associated with increased suicide risk for young females19. MMLs may support health outcomes that lead to improved employment outcomes11. MMLs are associated with a reduced likelihood of missing work20, decreased pain, improved overall health, increased days worked21, and reduced workplace fatalities22. Effects on employment outcomes are likely strongest for people with qualifying conditions under MMLs18, 21.
Evidence of the effects of MMLs on opioid outcomes is mixed. MMLs were initially associated with declines in opioid prescribing and opioid-related mortality and use; however, more recent studies suggest that trend has reversed and MMLs are now associated with increases in opioid-related mortality and use11, 23, 24, 25. Determining effects of MMLs on opioid outcomes is challenged by the changing nature of the opioid epidemic (e.g. introduction of fentanyl)11, 24, the fact that only 2.5% of the U.S. population uses medical marijuana26, and the differences in accessibility in each state27. Available evidence of the impact of MMLs on alcohol use is mixed11, 28, with most studies finding either no impact or a decrease in levels of alcohol use.
It is uncertain what effects MMLs may have on traffic crashes and fatalities; available evidence suggests they are associated with increases in driving under the influence of marijuana and decreases in crashes and fatalities11, 29, 30. The effects of MMLs on crime are unclear11.
Smoking marijuana may increase the risk of marijuana dependence (e.g. cannabis use disorder),2, 13, respiratory problems, heart attacks, cancers4, 31; it may increase the risk of psychotic and schizophrenic symptoms32, 33. Marijuana initiation before adulthood may increase the likelihood of dependence and related harms32, 33, 34; initiation over the age of 25 rarely results in dependence33.
How could this strategy advance health equity? This strategy is rated inconclusive impact on disparities.
It is unclear what impact medical marijuana legalization could have on disparities in medical marijuana accessibility and marijuana-related arrests39, 40, 41. Medical marijuana laws (MMLs) have been enacted in almost 40 states, yet marijuana remains a federally classified Schedule I narcotic, making possession or use of marijuana a criminal act under federal code37. More research is needed to determine effects42.
Experts suggest that there may be disparities in medical marijuana accessibility driven by income, race and ethnicity, and physician characteristics39, particularly for patients who are Black or have low incomes42, 43, 44. This may be a result of discriminatory practices in medication access and could further increase existing disparities in health and well-being39. For example, medical marijuana use is more common among individuals who are employed, have health insurance, and earn high incomes39. Other barriers to accessibility can include the costs of medical marijuana certification39, 42 and fewer available medical marijuana services in census tracts with more Black residents or those with low incomes44. Additionally, health care providers’ unconscious bias and prejudices can affect their decision-making and prescribing patterns in clinical settings45.
Available evidence indicates these accessibility barriers may increase the possibility that patients of color or patients with lower incomes may consider alternatives, including illicit42, 43 or recreational drug markets43. Black people appear to use medical marijuana less than white people; experts suggest that marijuana prohibition and its disproportionate impact on communities of color partially explain this difference39, 41.
What is the relevant historical background?
Marijuana has been used therapeutically for millennia38. It was first introduced in the U.S. in the early 1600s to produce hemp and was commonly used by physicians to treat a variety of health ailments until the early 20th century37. States started to ban marijuana in the 1910s when marijuana began to be negatively associated with both Black people and Mexican immigrants41. These efforts culminated with federal marijuana prohibition in 193741. The federal ban of the possession, consumption, and sale of marijuana led to openly racist enforcement tactics that have disproportionately harmed people of color41. While the state and federal laws did not explicitly ban medical use of marijuana, doctors were discouraged from prescribing it because of stigma, administrative burdens and taxes, and because they had access to more effective and standardized synthetic drugs38.
In 1971 President Nixon’s administration launched the “War on Drugs”37, 38, 41 and marijuana possession or use became a criminal act under the federal code38, leading to a massive expansion in marijuana criminalization with significant racial disparities in enforcement37, 41. Proponents of enforcement used “dog whistle” politics and negative stereotyping through coded language (e.g. “tough on crime” and “law and order”) to reference and exploit white concerns about racial minorities, social movements, and perceived disorder41, and continue to do so in the current legalization landscape46.
Around this time, research emerged supporting marijuana’s therapeutic potential as an appetite stimulant, anticonvulsant, and as a treatment for glaucoma. A federal government commission issued a report that recommended decriminalizing personal possession and use to eliminate incarceration as a penalty for possession of a small quantity of marijuana, which was ignored on the federal level38. Several states enacted decriminalization laws during a time when there was an increase in young white adults smoking marijuana; scholars highlight these decriminalization efforts as a whitening of marijuana use to decrease their risk of incarceration41. Despite the efforts of grassroot organizers and policymakers to capitalize the changing legal landscape and emerging research on the medical benefits of marijuana, federal prohibition of marijuana did not change38. A new state-level approach arose in the 1990s with California’s Proposition 215 that legalized medical marijuana for state residents in 1996; the state-level approach remains the standard for legalization in the current landscape38.
Significant disparities in enforcement of marijuana laws have imposed arrests, prosecutions and convictions on individuals and communities, separated families, and deprived individuals of child custody, immigration status, voting rights, eligibility for public housing, financial aid for education, and access to employment40, 41. While recreational marijuana legalization efforts tend to adopt a racial justice lens to its advocacy efforts, medical marijuana legalization efforts do not38.
Disparities also exist in the emerging $1 billion marijuana industry. It is estimated that about 80% of marijuana business owners are white, highlighting how states prohibit people with marijuana convictions from receiving business licenses40, 41. Additionally, potential Black and Latino entrepreneurs are more likely to be denied small-business loans because of discriminatory lending practices, and to be charged higher interest rates and subjected to predatory terms when they receive a line of credit40. For example, in the Washington D.C. medical marijuana industry, there was only one non-white dispensary owner, leading D.C. lawmakers to require owners to have lived in D.C. for at least 6 months prior to get a license41.
Equity Considerations
- If your state has medical marijuana laws, do existing regulations create barriers for individuals with qualifying conditions? Who can help advocate with the necessary policymakers to reduce barriers?
- If your state does not have medical marijuana laws, who could be a partner in advocating for such laws in your state? How can coalitions navigate the political landscape to enact such laws in your state?
- Do current laws in your state systematically exclude those harmed by previous marijuana prohibition from the legalized medical marijuana industry? How can you advocate for change so those harmed by previous marijuana prohibition can participate in the medical marijuana industry?
Implementation Examples
As of April 2023, medical marijuana is legal in 38 states, three U.S. territories and Washington, D.C.; these states also have comprehensive medical marijuana and cannabis programs. Nine states allow limited use of low tetrahydrocannabinols (known as THC), high cannabidiol (CBD) products for specific medical conditions1. Most states apply an excise tax on the sale of marijuana at either the retail or wholesale level, or both levels, and base it on price, weight, or potency35. Furthermore, states may direct tax revenue toward public health purposes to balance the potential public health impacts of marijuana use36.
More lenient state MMLs typically require a doctor’s recommendation and some allowable medical condition, while more stringent laws require individuals who receive medical marijuana to be part of a patient registry37.
Experts note that interest in medical marijuana legalization will likely decrease with the increased support for recreational marijuana, in part because of the ineradicable racial discrimination in the enforcement of marijuana laws38. As of 2023, recreational marijuana is legal in 24 states and Washington, D.C.1.
Implementation Resources
Footnotes
* Journal subscription may be required for access.
1 NCSL-Marijuana - National Conference of State Legislatures (NCSL). Marijuana overview.
2 Pacula 2017 - Pacula RL, Smart R. Medical marijuana and marijuana legalization. Annual Review of Clinical Psychology. 2017;13(1):397-419.
3 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.
4 NASEM 2017 - National Academies of Sciences, Engineering, and Medicine (NASEM). The health effects of cannabis and cannabinoids: The current state of evidence and recommendations for research. Washington, D.C.: The National Academies Press; 2017.
5 Whiting 2015 - Whiting PF, Wolff RF, Deshpande S, et al. Cannabinoids for medical use: A systematic review and meta-analysis. JAMA. 2015;313(24):2456-2473.
6 Hill 2015 - Hill KP. Medical marijuana for treatment of chronic pain and other medical and psychiatric problems: A clinical review. JAMA. 2015;313(24):2474-2483.
7 Koppel 2014 - Koppel BS, Brust JCM, Fife T, et al. Systematic review: Efficacy and safety of medical marijuana in selected neurologic disorders: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2014;82(17):1556-1563.
8 Cinti 2009 - Cinti S. Medical marijuana in HIV-positive patients: What do we know? Journal of the International Association Providers of AIDS Care. 2009;8(6):342-6.
9 Campbell-Sevigny 2023 - Sevigny EL, Greathouse J, Medhin DN. Health, safety, and socioeconomic impacts of cannabis liberalization laws: An evidence and gap map. Campbell Systematic Reviews. 2023;19(4).
10 Pawar 2024 - Pawar AKS, Firmin ES, Wilens TE, Hammond CJ. Systematic review and meta-analysis: Medical and recreational cannabis legalization and cannabis use among youth in the United States. Journal of the American Academy of Child and Adolescent Psychiatry. 2024.
11 Anderson 2023 - Anderson DM, Rees DI. The public health effects of legalizing marijuana. Journal of Economic Literature. 2023;61(1):86-143.
12 Melchior 2019 - Melchior M, Nakamura A, Bolze C, et al. Does liberalisation of cannabis policy influence levels of use in adolescents and young adults? A systematic review and meta-analysis. BMJ Open. 2019;9(7).
13 Smart 2019 - Smart R, Pacula RL. Early evidence of the impact of cannabis legalization on cannabis use, cannabis use disorder, and the use of other substances: Findings from state policy evaluations. American Journal of Drug and Alcohol Abuse. 2019;45(6):644-663.
14 Sarvet 2018 - Sarvet AL, Wall MM, Fink DS, et al. Medical marijuana laws and adolescent marijuana use in the United States: A systematic review and meta-analysis. Addiction. 2018;113(6):1003-1016.
15 Allaf 2023 - Allaf S, Lim JS, Buckley NA, Cairns R. The impact of cannabis legalization and decriminalization on acute poisoning: A systematic review. Addiction. 2023;118(12):2252-2274.
16 RAND-Pacula 2017 - Pacula RL. Regulating medical marijuana markets: Insights from scientific evaluations of state experiments. Santa Monica: RAND Corporation; 2017.
17 Wilson 2022 - Wilson S, Rhee SH. Causal effects of cannabis legalization on parents, parenting, and children: A systematic review. Preventive Medicine. 2022;156(August 2021):106956.
18 Kalbfuss 2024 - Kalbfuss J, Odermatt R, Stutzer A. Medical marijuana laws and mental health in the United States. Health Economics, Policy and Law. 2024:1-16.
19 Hammond 2024 - Hammond CJ, Hyer JM, Boustead AE, et al. Association between marijuana laws and suicide among 12- to 25-year-olds in the United States from 2000 to 2019. Journal of the American Academy of Child and Adolescent Psychiatry. 2024;63(3):345-354.
20 Ullman 2017 - Ullman DF. The effect of medical marijuana on sickness absence. Health Economics (United Kingdom). 2017;26(10):1322-1327.
21 Nicholas 2019 - Nicholas LH, Maclean JC. The effect of medical marijuana laws on the health and labor supply of older adults: Evidence from the health and retirement study. Journal of Policy Analysis and Management. 2019;38(2):455-480.
22 Anderson 2018 - Anderson DM, Rees DI, Tekin E. Medical marijuana laws and workplace fatalities in the United States. International Journal of Drug Policy. 2018;60(January):33-39.
23 Nguyen 2024 - Nguyen HV, McGinty EE, Mital S, Alexander GC. Recreational and medical cannabis legalization and opioid prescriptions and mortality. JAMA Health Forum. 2024;5(1):E234897.
24 Mathur 2023 - Mathur NK, Ruhm CJ. Marijuana legalization and opioid deaths. Journal of Health Economics. 2023;88(January):102728.
25 Smith 2020b - Smith RA. The effects of medical marijuana dispensaries on adverse opioid outcomes. Economic Inquiry. 2020;58(2):569-588.
26 Shover 2019 - Shover CL, Davis CS, Gordon SC, Humphreys K. Association between medical cannabis laws and opioid overdose mortality has reversed over time. Proceedings of the National Academy of Sciences of the United States of America. 2019;116(26):12624-12626.
27 Powell 2018 - Powell D, Pacula RL, Jacobson M. Do medical marijuana laws reduce addictions and deaths related to pain killers? Journal of Health Economics. 2018;58:29-42.
28 Pacula 2022 - Pacula RL, Smart R, Lira MC, et al. Relationships of cannabis policy liberalization with alcohol use and co-use with cannabis: A narrative review. Alcohol Research: Current Reviews. 2022;42(1).
29 Chen 2023a - Chen W, French MT. Marijuana legalization and traffic fatalities revisited. Southern Economic Journal. 2023;90(2):259-276.
30 Windle 2022 - Windle SB, Socha P, Nazif-Munoz JI, Harper S, Nandi A. The impact of cannabis decriminalization and legalization on road safety outcomes: A systematic review. American Journal of Preventive Medicine. 2022;63(6):1037-1052.
31 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.
32 Caulkins 2012 - Caulkins JP, Hawken A, Kilmer B, Kleiman MAR. Marijuana legalization: What everyone needs to know. New York: Oxford University Press; 2012.
33 Bostwick 2012 - Bostwick JM. Blurred boundaries: The therapeutics and politics of medical marijuana. Mayo Clinic Proceedings. 2012;87(2):172-86.
34 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.
35 NCSL-Brainerd 2021 - Brainerd J. State cannabis taxation. National Conference of State Legislatures (NCSL). 2021.
36 NCSL-PH Marijuana - National Conference of State Legislatures (NCSL). How four states incorporated public health into cannabis policy. 2022.
37 NBER-Dave 2022 - Dave D, Liang Y, Muratori C, Sabia J. The effects of recreational marijuana legalization on employment and earnings. National Bureau of Economic Research (NBER). 2022: Working Paper 30813.
38 Grossman 2021 - Grossman LA. Life, liberty, [and the pursuit of happiness]. In: Choose Your Medicine. New York: Oxford University Press; 2021:225-256.
39 Valencia 2017 - Valencia CI, Asaolu IO, Ehiri JE, Rosales C. Structural barriers in access to medical marijuana in the USA: A systematic review protocol. Systematic Reviews. 2017;6(1):1-8.
40 Crawford 2021 - Crawford NN. We’d go well together: A critical race analysis of marijuana legalization and expungement in the United States. Public Integrity. 2021;23(5):459-483.
41 Schlussel 2017 - Schlussel D. The mellow pot-smoker: White individualism in marijuana legalization campaigns. California Law Review. 2017;105(3):885-928.
42 Ashare 2023 - Ashare R, Turay E, Worster B, et al. Social determinants of health associated with how cannabis is obtained and used in patients with cancer receiving care at a cancer treatment center in Pennsylvania. Cannabis: Publication of the Research Society on Marijuana. 2023;6(2).
43 Mahabir 2021 - Mahabir VK, Smith CS, Vannabouathong C, Merchant JJ, Garibaldi AL. Comparing medical cannabis use in 5 U.S. states: A retrospective database study. Journal of Cannabis Research. 2021;3(1).
44 Cunningham 2022 - Cunningham CO, Zhang C, Hollins M, et al. Availability of medical cannabis services by racial, social, and geographic characteristics of neighborhoods in New York: A cross-sectional study. BMC Public Health. 2022;22(1):1-9.
45 Salmond 2019 - Salmond S, Allread V. A population health approach to America’s opioid epidemic. Orthopaedic Nursing. 2019;38(2):95-108.
46 Mortenson 2020 - Mortensen TM, Moscowitz L, Wan A, Yang A. The marijuana user in U.S. news media: An examination of visual stereotypes of race, culture, criminality and normification. Visual Communication. 2020;19(2):231-255.
Related What Works for Health Strategies
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