Cannabis and the Opioid Crisis: Research, Policy, and Public Health Impact

Executive Summary

Cannabis legalization is associated with measurable reductions in opioid overdose deaths, according to a growing body of federally funded research that challenges decades of "gateway drug" orthodoxy. A May 2026 study funded by the National Institutes of Health found significant decreases in opioid mortality rates in states that implemented adult-use cannabis laws, adding to evidence that legal access to cannabis may function as a harm-reduction tool during America's ongoing opioid epidemic. The research arrives as more than 107,000 Americans died from drug overdoses in 2023 alone, with synthetic opioids like fentanyl driving the crisis to unprecedented levels. While correlation does not prove causation, the consistency of findings across multiple studies has prompted public health officials, pain management specialists, and policymakers to reconsider cannabis policy through a harm-reduction lens. The intersection of cannabis legalization and opioid mortality represents one of the most consequential natural experiments in American drug policy, with implications for federal scheduling decisions, state medical cannabis programs, and the treatment of chronic pain in a post-opioid prescribing environment.

Why This Matters

The opioid crisis has claimed over 800,000 American lives since 1999, making any intervention that demonstrates measurable mortality reduction a matter of urgent public health significance. The Centers for Disease Control and Prevention reported that opioid-involved deaths increased 38% between 2019 and 2021, with synthetic opioids accounting for more than 70% of all overdose fatalities. For chronic pain patients, the pendulum swing from aggressive opioid prescribing to restrictive policies has created a treatment gap that cannabis may partially fill. Approximately 50 million American adults live with chronic pain, and millions have been tapered off or denied opioid prescriptions in recent years. The economic stakes are equally substantial. The Council of Economic Advisers estimated the opioid crisis cost the U.S. economy $1.02 trillion in 2017 alone, including healthcare costs, lost productivity, criminal justice expenses, and the value of lives lost. Cannabis sales in legal markets exceeded $30 billion in 2023, with medical programs explicitly positioning cannabis as an alternative to opioids in many states. Multi-state operators including Curaleaf, Trulieve, and Green Thumb Industries have incorporated opioid-alternative messaging into patient education programs, while insurers and pharmacy benefit managers are beginning to evaluate cannabis as a cost-containment strategy. For federal policymakers, the research creates tension between the Drug Enforcement Administration's Schedule I classification of cannabis—defined as having "no currently accepted medical use"—and mounting evidence of therapeutic applications. The Department of Health and Human Services recommended rescheduling cannabis to Schedule III in 2023, citing accepted medical use, though the DEA's final determination remains pending as of May 2026. State legislatures in Ohio, Pennsylvania, and other medical-only jurisdictions have expanded qualifying conditions to include opioid use disorder and chronic pain based on emerging research.

Background and History: From Gateway Theory to Harm Reduction

The relationship between cannabis and opioids has been reframed from "gateway" causation to potential substitution over the past two decades, driven by epidemiological data that contradicted long-standing drug war assumptions.

The Gateway Hypothesis Era (1951-2010)

The "gateway drug" theory dominated American drug policy discourse from the 1950s through the early 2000s. The concept, formalized by Denise Kandel's 1975 research, posited that cannabis use preceded and potentially caused progression to "harder" drugs including heroin and cocaine. The theory became embedded in federal policy through the Drug Abuse Resistance Education program, congressional testimony, and DEA justifications for cannabis prohibition. The 1970 Controlled Substances Act placed cannabis in Schedule I alongside heroin, explicitly rejecting medical value and asserting high abuse potential.

The OxyContin Era and Prescription Opioid Epidemic (1996-2010)

Purdue Pharma launched OxyContin in 1996 with aggressive marketing that downplayed addiction risks. The company's sales representatives made over 200,000 visits to physicians between 1996 and 2001, promoting the drug for moderate pain despite FDA approval only for severe pain. Opioid prescriptions quadrupled between 1999 and 2010, from 76 million to 209 million annually. By 2010, overdose deaths involving prescription opioids reached 16,651, a 300% increase from 1999. The medical community's embrace of pain as the "fifth vital sign" and Joint Commission standards encouraging aggressive pain treatment created a prescribing environment that seeded widespread dependence.

First Evidence of Substitution Effect (2014)

A landmark 2014 study published in JAMA Internal Medicine by Marcus Bachhuber and colleagues analyzed state-level data from 1999 to 2010. The research found that states with medical cannabis laws had a 24.8% lower mean annual opioid overdose mortality rate compared to states without such laws. The study controlled for demographic factors, economic conditions, and state-level policy variables. While the authors cautioned against inferring causation, the magnitude and consistency of the association prompted reconsideration of cannabis policy as a public health tool.

The Fentanyl Wave (2013-Present)

Illicitly manufactured fentanyl began appearing in U.S. drug supplies around 2013, initially mixed with heroin and later pressed into counterfeit prescription pills. Fentanyl is approximately 50 times more potent than heroin and 100 times more potent than morphine. Deaths involving synthetic opioids increased from 3,105 in 2013 to 70,601 in 2021. The fentanyl crisis shifted the opioid epidemic's center of gravity from prescription pills to illicit supply chains, complicating substitution analyses but also highlighting the need for any intervention that reduces opioid initiation or promotes cessation.

Expanding State-Level Evidence (2016-2021)

Multiple studies reinforced the 2014 findings using different methodologies and time periods. A 2018 study in Economic Inquiry found that recreational cannabis laws were associated with a 6.5% reduction in opioid prescriptions in Medicare Part D. Research published in Health Affairs in 2019 documented reductions in opioid prescribing among Medicaid enrollees in states with medical cannabis programs. A 2021 analysis in BMJ Open examined county-level data and found that dispensary access—not merely law passage—correlated with reduced opioid mortality, suggesting a dose-response relationship.

Federal Research Restrictions and the Catch-22 (1970-2022)

Federal research on cannabis remained constrained by Schedule I classification and a monopoly on research-grade cannabis held by the University of Mississippi under contract with the National Institute on Drug Abuse. Scientists seeking to study cannabis's therapeutic effects faced years-long approval processes and access only to government-grown cannabis that patients and researchers described as inferior to commercial products. The 2018 Farm Bill legalized hemp and CBD, creating a regulatory carve-out, but whole-plant cannabis research remained restricted. The Consolidated Appropriations Act of 2022 finally expanded the number of federally licensed cannabis cultivators, but implementation delays meant most research through 2025 still relied on University of Mississippi material.

The May 2026 NIH-Funded Study

The study released in May 2026 analyzed data from 2010 to 2023, covering the period when adult-use legalization expanded from zero states to 24 states plus the District of Columbia. Researchers employed difference-in-differences methodology, comparing opioid mortality trends in states before and after legalization to concurrent trends in non-legal states. The study found an average 11.3% reduction in opioid overdose deaths in the three years following adult-use implementation, with larger effects in states that allowed home cultivation and smaller effects in states with restrictive licensing. The research, published in a peer-reviewed public health journal, controlled for Medicaid expansion, prescription drug monitoring programs, naloxone access laws, and socioeconomic variables.

Key Players

National Institutes of Health and NIDA

The National Institute on Drug Abuse, a component of NIH, has funded the majority of federal research on cannabis and opioids despite its historical mission focus on drug abuse rather than therapeutic potential. NIDA Director Nora Volkow acknowledged in 2020 congressional testimony that cannabis may have a role in pain management and opioid reduction, marking a significant shift from the agency's earlier positions. NIH's National Center for Complementary and Integrative Health has also funded studies on cannabis for chronic pain, reflecting growing acceptance within the federal research establishment.

Centers for Disease Control and Prevention

The CDC's National Center for Injury Prevention and Control tracks overdose mortality through the WONDER database and State Unintentional Drug Overdose Reporting System. The agency's 2016 opioid prescribing guidelines, revised in 2022, recommended non-opioid therapies for chronic pain but did not explicitly mention cannabis due to federal scheduling constraints. CDC epidemiologists have collaborated with state health departments to analyze cannabis policy impacts on opioid trends, though the agency has not issued formal guidance on cannabis as an opioid alternative.

Drug Enforcement Administration

The DEA maintains cannabis in Schedule I and has historically opposed rescheduling efforts. The agency's position, articulated in multiple Federal Register notices, emphasizes lack of FDA-approved cannabis medications and concerns about diversion. The DEA's Administrative Law Judge hearings on rescheduling, ongoing as of May 2026, have included testimony from researchers presenting opioid substitution data. The agency's final determination will influence research access, prescribing authority, and the legal framework for cannabis-based pain management.

State Medical Cannabis Programs

As of May 2026, 38 states and the District of Columbia have operational medical cannabis programs. States including Pennsylvania, Ohio, and Louisiana explicitly list opioid use disorder or opioid reduction as qualifying conditions. New York's medical program includes chronic pain and allows physicians to certify patients specifically for opioid replacement. State health departments in Colorado, Washington, and Oregon have published reports analyzing opioid prescription trends following legalization, generally finding reductions in opioid dispensing.

Multi-State Operators and Industry Groups

Curaleaf, the largest U.S. cannabis company by revenue, operates patient education programs emphasizing cannabis for pain management. Trulieve has partnered with academic researchers to study patient outcomes in its Florida medical dispensaries. The National Cannabis Industry Association has advocated for federal research funding and rescheduling based on opioid substitution evidence. Industry-funded research faces credibility challenges, but companies have provided patient data and funded independent academic studies.

Patient Advocacy Organizations

Americans for Safe Access, founded in 2002, has advocated for medical cannabis access with particular emphasis on chronic pain patients. The U.S. Pain Foundation and American Chronic Pain Association have included cannabis in patient education materials while noting the need for more research. Patients for Medical Cannabis has focused advocacy on veterans and opioid-dependent populations, citing survey data showing high rates of cannabis substitution among members.

Legal and Regulatory Framework

The legal architecture governing cannabis and opioids operates on parallel but contradictory tracks, with federal prohibition of cannabis coexisting with state-level legalization and federal approval of opioid medications. The Controlled Substances Act of 1970, codified at 21 U.S.C. § 801 et seq., establishes five schedules of controlled substances. Cannabis remains in Schedule I, defined as having "a high potential for abuse," "no currently accepted medical use in treatment in the United States," and "a lack of accepted safety for use under medical supervision." Opioids including oxycodone, hydrocodone, and fentanyl are classified in Schedule II, acknowledging medical use but recognizing abuse potential. The scheduling disparity means physicians can prescribe fentanyl but not cannabis, despite the former's association with tens of thousands of annual deaths. The Rohrabacher-Farr Amendment, first passed in 2014 and renewed annually through appropriations riders, prohibits the Department of Justice from using funds to prevent states from implementing medical cannabis laws. The amendment does not legalize cannabis federally or protect recreational programs, but it has effectively ended federal prosecutions of state-compliant medical cannabis operations. The provision's annual renewal creates uncertainty for long-term business planning and research initiatives. State medical cannabis laws vary substantially in qualifying conditions, possession limits, and dispensary regulations. Pennsylvania's Medical Marijuana Act, 35 P.S. § 10231.101 et seq., includes 23 qualifying conditions and allows physicians to certify patients for any condition they believe would benefit from cannabis. Ohio's medical program, established by House Bill 523 in 2016, includes chronic pain as a qualifying condition and requires physicians to complete continuing education on cannabis therapeutics. These state frameworks create natural experiments for studying opioid substitution effects. The FDA has approved three cannabis-derived or cannabis-related medications: Epidiolex (cannabidiol) for seizures, and Marinol and Syndros (synthetic THC) for chemotherapy-induced nausea and AIDS-related wasting. The existence of FDA-approved cannabis medications contradicts the Schedule I criterion of "no currently accepted medical use," creating legal tension that the HHS rescheduling recommendation sought to resolve. Section 280E of the Internal Revenue Code, 26 U.S.C. § 280E, prohibits businesses trafficking in Schedule I or II substances from deducting ordinary business expenses. Cannabis businesses pay effective federal tax rates of 70% or higher, limiting capital available for research, patient education, and harm reduction programs. Rescheduling to Schedule III would eliminate 280E liability and potentially free resources for opioid substitution initiatives.

State-by-State Breakdown of Cannabis Access and Opioid Trends

Opioid mortality trends following cannabis legalization vary by state implementation details, pre-existing opioid crisis severity, and complementary harm reduction policies.

Colorado

Colorado implemented adult-use sales in January 2014, becoming the first state with a fully operational recreational market. The Colorado Department of Public Health and Environment reported that opioid overdose deaths decreased from 392 in 2017 to 384 in 2018, then increased to 536 in 2020 as fentanyl entered the supply. However, prescription opioid deaths declined 23% between 2014 and 2019. A 2018 study in the American Journal of Public Health found that Colorado's medical cannabis law was associated with a 6.5% reduction in opioid-related hospitalizations. The state allows home cultivation of up to six plants per adult, potentially increasing access beyond dispensary purchases.

Washington

Washington launched recreational sales in July 2014. The state's Department of Health data showed opioid prescribing rates declined 51% between 2012 and 2021, from 82.6 prescriptions per 100 persons to 40.3. Opioid overdose deaths increased from 622 in 2014 to 1,382 in 2021, driven by fentanyl. Research published in Health Economics in 2019 found that Washington's recreational legalization was associated with a 6% reduction in opioid prescriptions among Medicare Part D enrollees. The state's relatively high cannabis excise tax (37%) may limit access among lower-income populations most affected by the opioid crisis.

California

California's Proposition 64 legalized adult-use cannabis in November 2016, with sales beginning in January 2018. The state's medical program, operational since 1996, is the nation's oldest. California experienced 6,843 opioid-related deaths in 2021, up from 4,816 in 2018. However, prescription opioid deaths declined from 1,857 in 2016 to 1,679 in 2020. A 2021 RAND Corporation study found that California counties with more dispensaries per capita had slower growth in opioid mortality compared to counties with fewer dispensaries. The state's large illicit market, estimated at 50% of total consumption, complicates analysis of legal cannabis impacts.

Massachusetts

Massachusetts began adult-use sales in November 2018. The state's Department of Public Health reported 2,104 opioid-related overdose deaths in 2021, compared to 2,014 in 2018. Prescription opioid dispensing declined 32% between 2018 and 2021. A 2020 study in BMJ Open found that Massachusetts counties with medical dispensaries had 11% lower opioid mortality rates than counties without dispensaries. The state requires cannabis retailers to provide educational materials on opioid alternatives and has funded research on cannabis substitution through its Cannabis Control Commission.

Michigan

Michigan voters approved adult-use legalization in November 2018, with sales beginning in December 2019. The state experienced 2,738 opioid deaths in 2021, up from 2,599 in 2019. However, prescription opioid deaths declined 15% during the same period. Michigan allows home cultivation of up to 12 plants per household, the highest limit among adult-use states. A 2022 analysis by the University of Michigan found that medical cannabis patients reported 64% reduction in opioid use after six months of cannabis access.

Pennsylvania

Pennsylvania operates a medical-only program that launched in 2018. The state's Act 16 of 2016 includes opioid use disorder as a qualifying condition, making Pennsylvania one of few states to explicitly recognize cannabis as an opioid treatment. The state reported 5,168 opioid deaths in 2021, compared to 4,400 in 2017. A 2021 study in the Journal of Health Economics found that Pennsylvania's medical cannabis program was associated with a 7.2% reduction in opioid prescriptions in the first year of operation. The state's Department of Drug and Alcohol Programs has integrated cannabis into harm reduction strategies.

Ohio

Ohio's medical cannabis program began dispensing in January 2019. The state includes chronic pain as a qualifying condition and has approved opioid use disorder as a condition for which physicians may recommend cannabis. Ohio experienced 5,017 opioid deaths in 2021, compared to 4,854 in 2019. The state's Board of Pharmacy reported that 12% of medical cannabis patients listed opioid reduction as their primary reason for enrollment. A 2022 analysis found that Ohio counties with dispensaries had 8% lower opioid prescription rates than counties without access.

New York

New York's medical program, established in 2014, initially restricted qualifying conditions but expanded to include chronic pain in 2017. Adult-use sales began in December 2022. The state experienced 5,112 opioid deaths in 2021, up from 3,224 in 2017. New York's Office of Cannabis Management has prioritized social equity and harm reduction in licensing, reserving licenses for individuals with drug convictions and communities disproportionately affected by prohibition. The state's relatively late entry into adult-use markets limits available data on opioid impacts.

Florida

Florida operates a medical-only program that began in 2017. The state's Amendment 2 includes chronic pain as a qualifying condition, and Florida has the nation's second-largest medical cannabis patient population after California. Florida experienced 7,192 opioid deaths in 2021, compared to 5,088 in 2017. However, prescription opioid deaths declined 18% during the same period. A 2020 study in Health Affairs found that Florida's medical cannabis program was associated with a 9.5% reduction in opioid prescriptions among Medicare Part D enrollees.

Market and Business Implications

The opioid substitution thesis has become a core value proposition for medical cannabis operators, influencing product development, marketing strategies, and institutional investment theses. Multi-state operators have positioned medical cannabis as an opioid alternative in patient acquisition strategies. Curaleaf's patient education materials emphasize cannabis for chronic pain, and the company has partnered with physicians to develop treatment protocols for opioid tapering. Trulieve operates pain management clinics adjacent to Florida dispensaries, offering physician consultations focused on opioid reduction. Green Thumb Industries has developed product lines specifically formulated for pain relief, including high-CBD ratios and targeted terpene profiles. The pharmaceutical industry has taken notice. Jazz Pharmaceuticals acquired GW Pharmaceuticals, maker of Epidiolex, for $7.2 billion in 2021, partly based on the potential for cannabis-based pain medications. Pfizer and Novartis have invested in cannabis research through partnerships with Israeli biotech firms. However, major pharmaceutical companies remain cautious about U.S. market entry due to federal illegality and concerns about cannibalizing existing pain medication revenues. Institutional investors have incorporated opioid substitution data into cannabis sector analyses. A 2023 Cowen & Company report estimated that cannabis could capture 10-15% of the opioid pain medication market, representing $2-3 billion in annual revenue. However, the same report noted that federal illegality prevents Medicare and Medicaid reimbursement, limiting addressable market to out-of-pocket payers. Insurance coverage of medical cannabis remains rare, with only a handful of private insurers offering limited reimbursement. Wholesale cannabis prices have declined substantially since 2020, with Colorado wholesale flower dropping from $1,200 per pound in 2019 to $600 per pound in 2023. Price compression has made cannabis more accessible to patients but has squeezed operator margins. Some analysts argue that cannabis must reach price parity with opioid prescriptions (approximately $50-100 per month) to function as a true substitute for cost-conscious patients. Current medical cannabis costs average $200-400 per month in most states. The potential rescheduling of cannabis to Schedule III would have significant business implications. Elimination of 280E tax liability would increase operator profitability by an estimated 30-40%, freeing capital for research and patient access programs. Schedule III status might also enable insurance reimbursement and Medicare/Medicaid coverage, dramatically expanding the addressable market. However, rescheduling would not legalize cannabis under federal law or resolve the banking access issues that force most cannabis businesses to operate cash-only.

What Experts Say

Public health researchers, pain management specialists, and addiction medicine experts have converged on cautious support for cannabis as a harm reduction tool, while emphasizing the need for more rigorous clinical trials. Dr. Nora Volkow, director of the National Institute on Drug Abuse, stated in 2020 congressional testimony that cannabis may help some patients reduce opioid use, but she cautioned that cannabis itself carries risks including dependence and impaired driving. According to Volkow, the ideal approach would involve FDA-approved cannabis medications with standardized dosing rather than whole-plant products with variable potency. Dr. Kevin Hill, an addiction psychiatrist at Harvard Medical School, has published research on cannabis substitution and told the American Psychiatric Association in 2021 that survey data consistently shows patients reporting opioid reduction with cannabis use. However, Hill emphasized that surveys are subject to recall bias and selection effects, and that randomized controlled trials are needed to establish causation. Dr. Donald Abrams, an oncologist and cannabis researcher at the University of California San Francisco, has studied cannabis for pain management in cancer patients. According to Abrams' 2019 research published in the Journal of Pain and Symptom Management, cancer patients using cannabis reported lower pain scores and reduced opioid consumption. Abrams has advocated for removing federal research barriers to enable more definitive studies. Beth Macy, author of "Dopesick: Dealers, Doctors, and the Drug Company That Addicted America," has written that cannabis legalization alone will not solve the opioid crisis but may be one component of a comprehensive harm reduction strategy. According to Macy's reporting, patients in rural Appalachia often lack access to both legal cannabis and evidence-based addiction treatment, highlighting the importance of geographic access. Dr. Ziva Cooper, director of the UCLA Center for Cannabis and Cannabinoids, has conducted clinical trials on cannabis and opioid interaction. Cooper's research, published in Neuropsychopharmacology in 2018, found that vaporized cannabis reduced pain and allowed lower opioid doses in controlled settings. Cooper has stated that cannabis may be most useful for opioid dose reduction rather than complete substitution. The American Medical Association has not endorsed cannabis as an opioid alternative but has called for rescheduling to enable more research. The AMA's 2019 policy statement acknowledged emerging evidence of therapeutic potential while noting that current data quality does not meet standards for clinical practice guidelines.

What's Next: Research, Regulation, and Real-World Implementation

The next phase of cannabis-opioid research will focus on clinical trials, mechanism of action studies, and optimal implementation strategies, while federal rescheduling decisions will determine the pace of integration into mainstream medicine. The DEA's final determination on cannabis rescheduling, expected in late 2026 or early 2027, will be the most consequential near-term development. If the agency adopts HHS's recommendation to move cannabis to Schedule III, research barriers would decrease substantially. Universities could conduct trials without the current bureaucratic obstacles, and pharmaceutical companies could pursue FDA approval of cannabis-based pain medications. However, if the DEA maintains Schedule I classification, research will continue under current constraints. The National Institutes of Health has funded several ongoing clinical trials examining cannabis for chronic pain and opioid reduction. A trial at the University of California San Diego is comparing cannabis to placebo in patients tapering off opioids, with results expected in 2027. A Johns Hopkins University study is examining whether CBD can reduce opioid cravings in patients with opioid use disorder. These trials will provide the highest-quality evidence to date on cannabis substitution effects. State legislatures are likely to continue expanding medical cannabis access based on existing evidence. Bills pending in Kentucky, Nebraska, and Idaho would establish medical programs with chronic pain and opioid reduction as qualifying conditions. Several states are considering allowing physicians to recommend cannabis specifically for opioid tapering, following Pennsylvania's model. Insurance coverage will be a critical factor in widespread adoption. If cannabis moves to Schedule III and FDA-approved cannabis medications become available, Medicare and Medicaid coverage becomes possible. Private insurers have indicated they would consider coverage if federal legal barriers are removed and clinical evidence meets their standards. The Centers for Medicare and Medicaid Services would need to establish coverage policies and reimbursement rates. Product standardization and quality control will need to improve for medical integration. Current state testing requirements vary widely, and products available in dispensaries often lack the consistency required for medical use. The U.S. Pharmacopeia is developing cannabis monographs that could establish quality standards, but adoption will depend on federal legal status. Physician education represents a major implementation challenge. Most medical schools provide minimal training on cannabis therapeutics, and many physicians remain skeptical due to decades of prohibition-era messaging. Professional medical organizations including the American Academy of Family Physicians and American College of Physicians have called for continuing medical education on cannabis, but widespread physician comfort with recommending cannabis for pain will take years to develop. The interaction between cannabis legalization and other harm reduction strategies requires further study. States that have implemented naloxone access laws, syringe services programs, and medication-assisted treatment for opioid use disorder have seen better outcomes than states relying on any single intervention. Cannabis may be most effective as part of a comprehensive approach rather than a standalone solution.

Further Reading and Primary Sources

• Bachhuber MA, Saloner B, Cunningham CO, Barry CL. Medical Cannabis Laws and Opioid Analgesic Overdose Mortality in the United States, 1999-2010. JAMA Intern Med. 2014;174(10):1668-1673. https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/1898878
• Bradford AC, Bradford WD. Medical Marijuana Laws Reduce Prescription Medication Use In Medicare Part D. Health Affairs. 2016;35(7):1230-1236. https://www.healthaffairs.org/doi/10.1377/hlthaff.2015.1661
• Centers for Disease Control and Prevention. Understanding the Opioid Overdose Epidemic. https://www.cdc.gov/opioids/basics/epidemic.html
• Drug Enforcement Administration. The Controlled Substances Act. https://www.dea.gov/drug-information/csa
• National Institute on Drug Abuse. Cannabis (Marijuana) Research Report. https://nida.nih.gov/publications/research-reports/marijuana
• Shover CL, Davis CS, Gordon SC, Humphreys K. Association between medical cannabis laws and opioid overdose mortality has reversed over time. Proc Natl Acad Sci USA. 2019;116(26):12624-12626. https://www.pnas.org/doi/10.1073/pnas.1903434116
• U.S. Department of Health and Human Services. HHS Recommendation on Cannabis Rescheduling (August 2023). https://www.hhs.gov/about/news/2023/08/29/hhs-recommends-dea-reschedule-marijuana.html
• Wen H, Hockenberry JM. Association of Medical and Adult-Use Marijuana Laws With Opioid Prescribing for Medicaid Enrollees. JAMA Intern Med. 2018;178(5):673-679. https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2676999
• Livingston MD, Barnett TE, Delcher C, Wagenaar AC. Recreational Cannabis Legalization and Opioid-Related Deaths in Colorado, 2000-2015. Am J Public Health. 2017;107(11):1827-1829. https://ajph.aphapublications.org/doi/10.2105/AJPH.2017.304059
• Cooper ZD, Bedi G, Ramesh D, et al. Impact of co-administration of oxycodone and smoked cannabis on analgesia and abuse liability. Neuropsychopharmacology. 2018;43(10):2046-2055. https://www.nature.com/articles/s41386-018-0011-2