Medical marijuana legalization

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 conditions (NASEM 2017, Whiting 2015, Hill 2015, Koppel 2014, Cinti 2009). More research is needed to determine the effects of legalizing medical marijuana on long-term health, safety, and socioeconomic outcomes (Campbell-Sevigny 2023).

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 use (Pawar 2024, Anderson 2023, Melchior 2019, Smart 2019, Sarvet 2018). MMLs may be associated with increases in marijuana use among women who are pregnant (Wilson 2022). A higher density of medical marijuana dispensaries may be associated with increased marijuana use among adults and young adults (Cantor 2024, Shih 2019) and marijuana-related health harms, including healthcare service use and hospitalization during pregnancy due to marijuana (Cantor 2024). MMLs are associated with increased risk of unintentional toxic ingestions of marijuana products among adults, adolescents, and children (Allaf 2023, RAND-Pacula 2017).

Available evidence suggests mixed impacts on suicide risk. Some studies find that MMLs may be associated with decreased rates of suicide (Anderson 2023, Anderson 2014), while other studies find that MMLs are associated with increased suicide risk (Hammond 2024), and others did not find any association between MMLs and suicide risk (Grucza 2015). MMLs may be associated with fewer reported poor mental health days (Kalbfuss 2024) and support health outcomes that lead to improved employment outcomes (Anderson 2023). MMLs are associated with a reduced likelihood of missing work (Ullman 2017), decreased pain, improved overall health, increased days worked (Nicholas 2019), and a reduction in workplace fatalities (Anderson 2018). Effects on employment outcomes are likely strongest for people with qualifying conditions under MMLs (Nicholas 2019, Kalbfuss 2024).

Evidence of the effects of MMLs on opioid outcomes is mixed. MMLs were initially associated with declines in opioid-related mortality and use and other opioid outcomes such as reductions in opioid prescribing, however more recent studies suggest that trend has reversed and are now associated with increases (Anderson 2023, Nguyen 2024, Mathur 2023, Smith 2020b). Determining effects of MMLs on opioid outcomes is challenged by the changing nature of the opioid epidemic (e.g., introduction of fentanyl) (Anderson 2023, Mathur 2023), the fact that only 2.5% of the U.S. population uses medical marijuana (Shover 2019), and the differences in accessibility in each state (Powell 2018). Available evidence of the impact of MMLs on alcohol use is mixed (Anderson 2023, Pacula 2022), with most studies finding either no impact or a decrease in drinking levels.

It is uncertain the effects of MMLs 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 fatalities (Anderson 2023, Chen 2023, Windle 2022). The effects of MMLs on crime are unclear (Anderson 2023).

Smoking marijuana may increase the risk of marijuana dependence (e.g., cannabis use disorder) (Smart 2019, Pacula 2017), respiratory problems, heart attacks, and cancers (NASEM 2017, Leung 2011); it may increase the risk of psychotic and schizophrenic symptoms (Caulkins 2012, Bostwick 2012). Marijuana initiation before adulthood may increase the likelihood of dependence and related harms (Caulkins 2012, Wilsey 2008, Bostwick 2012); initiation over the age of 25 rarely results in dependence (Bostwick 2012).

It is unclear what impact medical marijuana legalization could have on disparities in medical marijuana accessibility and marijuana-related arrests (Valencia 2017, Crawford 2021, Schlussel 2017). 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 code (NBER-Dave 2022). More research is needed to determine effects (Ashare 2023).

Experts suggest that there may be disparities in medical marijuana accessibility driven by income, race and ethnicity, and physician characteristics (Valencia 2017), particularly for patients who are Black or have low incomes (Ashare 2023, Mahabir 2021, Cunningham 2022). This may be a result of discriminatory practices in medication access and could further increase existing disparities in health and well-being (Valencia 2017). For example, medical marijuana use is more common among individuals who are employed, have health insurance, and earn high incomes (Valencia 2017). Other barriers to accessibility can include the costs of medical marijuana certification (Valencia 2017, Ashare 2023) and fewer available medical marijuana services in census tracts with more Black residents or those with low incomes (Cunningham 2022). Additionally, health care providers’ unconscious bias and prejudices can affect their decision-making and prescribing patterns in clinical settings (Salmond 2019).

Available evidence indicates these accessibility barriers may increase the possibility that patients of color or patients with lower incomes may consider alternatives, including illicit (Ashare 2023, Mahabir 2021) or recreational drug markets (Mahabir 2021). 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 difference (Valencia 2017, Schlussel 2017).

Marijuana has been used therapeutically for millennia (Grossman 2021). 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 20^th century (NBER-Dave 2022). States started to ban marijuana in the 1910s when marijuana began to be negatively associated with both Black people and Mexican immigrants (Schlussel 2017). These efforts culminated with federal marijuana prohibition in 1937 (Schlussel 2017). The federal ban of the possession, consumption, and sale of marijuana led to openly racist enforcement tactics that have disproportionately harmed people of color (Schlussel 2017). 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 drugs (Grossman 2021).

In 1971 President Nixon’s administration launched the “War on Drugs” (NBER-Dave 2022, Grossman 2021, Schlussel 2017) and marijuana possession or use became a criminal act under the federal code (Grossman 2021), leading to a massive expansion in marijuana criminalization with significant racial disparities in enforcement (NBER-Dave 2022, Schlussel 2017). 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 disorder (Schlussel 2017), and continue to do so in the current legalization landscape (Mortenson 2020).

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 level (Grossman 2021). 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 incarceration (Schlussel 2017). 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 change (Grossman 2021). 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 landscape (Grossman 2021).

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 employment (Crawford 2021, Schlussel 2017). While recreational marijuana legalization efforts tend to adopt a racial justice lens to its advocacy efforts, medical marijuana legalization efforts do not (Grossman 2021).

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 licenses (Crawford 2021, Schlussel 2017). 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 credit (Crawford 2021). 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 license (Schlussel 2017).

• 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?

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 conditions (NCSL-Marijuana). 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 potency (NCSL-Brainerd 2021). Furthermore, states may direct tax revenue toward public health purposes to balance the potential public health impacts of marijuana use (NCSL-PH Marijuana). The Prescription Drug Abuse Policy System includes information on state laws and regulations governing production, sale, transport, quality and use of marijuana for therapeutic purposes (PDAPS).

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 registry (NBER-Dave 2022).

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 laws (Grossman 2021). As of 2023, recreational marijuana is legal in 24 states and Washington, D.C. (NCSL-Marijuana).

MPP - Marijuana policy project (MPP). We change laws.

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

PDAPS - Prescription Drug Abuse Policy System (PDAPS). (n.d.). A source of rigorous legal data for researchers and detailed policy information for the public. October 22, 2025.

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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.

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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.

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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.

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.