CBD and Opioid Interaction Research: Clinical Evidence and Safety

Executive Summary

Emerging research demonstrates that cannabidiol (CBD) may enhance the analgesic effects of opioid medications while potentially reducing the doses required for pain relief. Recent studies published in 2026 have reignited scientific and clinical interest in CBD-opioid interactions, with preclinical data suggesting that CBD can amplify oxycodone's pain-relieving properties through synergistic mechanisms involving the endocannabinoid system and opioid receptors. This research carries profound implications for the ongoing opioid crisis, as combination therapies could allow chronic pain patients to achieve adequate relief with lower opioid doses, potentially reducing risks of tolerance, dependence, and overdose. The findings arrive as the United States grapples with over 80,000 annual opioid-related deaths and as medical cannabis programs in 38 states increasingly serve patients seeking alternatives or adjuncts to conventional pain management. Federal restrictions under the Controlled Substances Act continue to complicate large-scale human trials, though state-level medical marijuana programs and evolving FDA guidance are creating pathways for expanded clinical investigation.

Why This Research Matters

The intersection of CBD and opioid pharmacology represents one of the most clinically significant areas of cannabis research, with direct implications for millions of chronic pain patients and the broader public health crisis of opioid addiction. Approximately 50 million American adults live with chronic pain, according to the Centers for Disease Control and Prevention, with roughly 20 million experiencing high-impact chronic pain that limits daily activities. Opioid analgesics remain the most commonly prescribed treatment for moderate to severe pain, yet their use carries substantial risks. The National Institute on Drug Abuse reported 81,806 opioid overdose deaths in 2023, with prescription opioids contributing to approximately 30% of these fatalities. Medical cannabis patients consistently cite pain management as their primary reason for use, with survey data from state registries showing 60-85% of cardholders seeking relief from chronic pain conditions. If CBD can enhance opioid efficacy while allowing dose reduction, the public health implications extend across multiple domains: reduced overdose risk, lower healthcare costs from opioid-related complications, decreased diversion of prescription medications, and improved quality of life for pain patients who currently face inadequate relief or intolerable side effects. The economic stakes are equally substantial. The opioid crisis costs the United States an estimated $1.02 trillion annually when accounting for healthcare expenses, lost productivity, criminal justice costs, and overdose deaths, according to 2023 analysis from the Society of Actuaries. The legal cannabis industry generated $33.6 billion in sales in 2023, with CBD products representing a $4.8 billion segment. Pharmaceutical companies, multi-state operators, and specialty pain management clinics are closely monitoring this research for potential product development and clinical protocol integration. Regulatory agencies face mounting pressure to facilitate research while maintaining safety standards. The Drug Enforcement Administration maintains CBD derived from marijuana as a Schedule I controlled substance, while hemp-derived CBD with less than 0.3% THC gained legal status under the 2018 Farm Bill. This regulatory bifurcation complicates research protocols and product development, even as the FDA has approved one CBD medication (Epidiolex) for seizure disorders, establishing precedent for cannabis-derived pharmaceuticals.

Background and History

Scientific investigation of cannabis-opioid interactions spans more than four decades, evolving from early animal studies to contemporary human trials examining therapeutic synergies and harm reduction potential.

Early Preclinical Research (1970s-1990s)

The foundation for CBD-opioid interaction research emerged from broader investigations into the endocannabinoid system. In 1988, researchers at the St. Louis University School of Medicine identified the first cannabinoid receptor (later designated CB1), establishing that cannabis compounds interact with specific biological targets. By 1993, the discovery of the CB2 receptor and endogenous cannabinoids like anandamide revealed a complex signaling system involved in pain modulation, immune function, and homeostasis. Early animal studies in the 1970s and 1980s demonstrated that THC could produce analgesic effects and showed cross-tolerance with morphine, suggesting overlapping mechanisms. However, CBD received less attention during this period, as researchers focused primarily on THC's psychoactive properties and therapeutic potential. The distinction between CBD's non-intoxicating effects and THC's psychoactivity would not become clinically relevant until the late 1990s.

Opioid Crisis Emergence (2000-2010)

The escalating opioid epidemic transformed the research landscape. Prescription opioid dispensing increased 402% between 1999 and 2010, according to CDC data, driven by aggressive pharmaceutical marketing, evolving pain management standards, and underestimation of addiction risks. By 2010, the United States consumed 99% of the global hydrocodone supply and 80% of oxycodone, despite representing only 5% of the world's population. This crisis catalyzed interest in alternative pain management strategies. A 2014 study published in JAMA Internal Medicine found that states with medical cannabis laws experienced 24.8% lower annual opioid overdose mortality rates compared to states without such laws, suggesting a potential substitution effect. While this ecological research could not establish causation, it prompted deeper investigation into mechanisms by which cannabis might reduce opioid use or enhance opioid therapy.

Endocannabinoid-Opioid System Interactions (2010-2020)

Neurobiological research revealed extensive crosstalk between endocannabinoid and opioid systems. Studies demonstrated that CB1 and mu-opioid receptors co-localize in key pain-processing regions including the periaqueductal gray, rostral ventromedial medulla, and dorsal horn of the spinal cord. Both systems modulate descending pain pathways and can produce synergistic analgesic effects when activated simultaneously. A landmark 2011 study in the Journal of Pain found that vaporized cannabis enhanced the analgesic effects of oxycodone in human subjects with experimentally induced pain. Researchers at the University of California, San Francisco administered low doses of oxycodone alone and in combination with vaporized cannabis, finding that the combination produced significantly greater pain relief than oxycodone alone without proportional increases in cognitive impairment. This human data supported earlier animal findings and suggested clinical potential for combination therapy. Research into CBD specifically gained momentum following the 2018 FDA approval of Epidiolex for Dravet syndrome and Lennox-Gastaut syndrome. This approval validated pharmaceutical-grade CBD as a legitimate therapeutic agent and spurred investigation into its broader applications. Unlike THC, CBD exhibits low affinity for CB1 and CB2 receptors but modulates pain through multiple mechanisms including serotonin receptor activation, TRPV1 channel modulation, and inhibition of anandamide reuptake.

Contemporary Research Focus (2020-Present)

The current research phase emphasizes CBD's unique pharmacological profile and its potential to address opioid-related harms. A 2019 study published in Neurotherapeutics found that CBD reduced heroin-seeking behavior in animal models, suggesting applications for addiction treatment. Human trials followed, with a 2019 double-blind study in the American Journal of Psychiatry demonstrating that CBD reduced cue-induced craving and anxiety in individuals with heroin use disorder. The 2026 research highlighting CBD's enhancement of oxycodone's analgesic effects represents a convergence of these investigative threads. Published studies have examined various CBD-opioid combinations, dosing ratios, and administration routes. Researchers are particularly interested in whether CBD can facilitate opioid dose reduction while maintaining pain control, a strategy known as opioid-sparing therapy. Federal policy shifts have incrementally expanded research access. The 2018 Farm Bill legalized hemp-derived CBD, while the DEA increased the marijuana research quota from 472 kilograms in 2018 to 3,200 kilograms in 2023. The National Institutes of Health allocated $196 million for cannabis research in fiscal year 2023, with substantial portions directed toward pain management and opioid interaction studies.

Key Players in CBD-Opioid Research

Academic Research Institutions

The University of California, San Diego Center for Medicinal Cannabis Research has conducted multiple federally-funded studies examining cannabis-opioid interactions since its establishment in 2000. The center's research portfolio includes clinical trials evaluating vaporized cannabis as an adjunct to opioid therapy for chronic pain, with findings published in journals including Clinical Pharmacology & Therapeutics and The Journal of Pain. Principal investigators have documented that cannabis can reduce opioid consumption by 40-60% in some chronic pain populations while maintaining or improving pain control. Johns Hopkins University School of Medicine operates a dedicated Cannabis Science Laboratory investigating CBD's molecular mechanisms and clinical applications. Researchers there have published extensively on CBD's effects on drug-seeking behavior and its potential role in addiction treatment. Their 2022 study in Drug and Alcohol Dependence found that CBD administration reduced opioid cravings in patients undergoing medication-assisted treatment for opioid use disorder. The University of Colorado Anschutz Medical Campus houses researchers examining CBD-opioid interactions in specific pain conditions including neuropathic pain and cancer-related pain. Their work has contributed to understanding how CBD's anti-inflammatory and neuroprotective properties may complement opioid analgesia through distinct mechanisms.

Federal Agencies

The National Institute on Drug Abuse serves as the primary federal funder of cannabis-opioid research, distributing grants totaling approximately $87 million annually for studies examining cannabis as both a potential harm reduction tool and a substance of abuse concern. NIDA maintains the only federally-legal source of research-grade cannabis through its contract with the University of Mississippi, though this monopoly has faced criticism for limited strain diversity and cannabinoid profiles that differ from commercial products. The Food and Drug Administration regulates clinical trials of CBD-opioid combinations and evaluates safety data for potential therapeutic applications. The agency's 2020 guidance on cannabis-derived compounds established pathways for investigational new drug applications, though the approval process remains lengthy and expensive. FDA scientists have raised concerns about CBD-opioid interactions including potential for enhanced sedation, respiratory depression, and altered opioid metabolism through cytochrome P450 enzyme inhibition. The Drug Enforcement Administration controls access to Schedule I substances including marijuana-derived CBD, requiring researchers to obtain special licenses and maintain stringent security protocols. The DEA's 2023 expansion of registered marijuana manufacturers from one to seven entities aimed to increase research access, though bureaucratic delays continue to impede study initiation.

Pharmaceutical Companies

GW Pharmaceuticals, now a subsidiary of Jazz Pharmaceuticals, pioneered pharmaceutical-grade CBD development with Epidiolex and maintains an active pipeline investigating CBD for pain management and neurological conditions. The company has filed multiple patents covering CBD-opioid combinations and delivery systems, though no products have reached market approval for pain indications. Jazz Pharmaceuticals reported $838 million in Epidiolex sales in 2023, demonstrating commercial viability for prescription CBD products. Zynerba Pharmaceuticals has developed a transdermal CBD gel and conducted Phase 2 trials examining its efficacy for various pain conditions. The company's research includes investigation of CBD's opioid-sparing potential, with preliminary data suggesting that transdermal CBD may reduce opioid requirements in post-surgical pain management. Several smaller biotechnology firms including Kalytera Therapeutics, Zelira Therapeutics, and Anebulo Pharmaceuticals are developing proprietary CBD formulations and conducting clinical trials for pain-related indications. These companies face significant regulatory and financial hurdles, with most operating at losses while advancing early-stage research.

Patient Advocacy Organizations

Americans for Safe Access, founded in 2002, advocates for medical cannabis research and patient access, including support for studies examining cannabis-opioid interactions. The organization has submitted comments to federal agencies urging expanded research access and has connected researchers with patient populations for clinical trial recruitment. The U.S. Pain Foundation represents chronic pain patients and has increasingly advocated for cannabis research as an alternative or complement to opioid therapy. The organization's 2023 patient survey found that 67% of chronic pain patients had tried cannabis products, with 71% of those reporting reduced opioid use after initiating cannabis therapy.

Legal and Regulatory Framework

The legal landscape governing CBD-opioid research reflects complex federal-state tensions, with the Controlled Substances Act creating barriers to investigation even as state medical marijuana programs expand access. The Controlled Substances Act of 1970, codified at 21 U.S.C. § 812, classifies marijuana as a Schedule I substance, defined as having high abuse potential, no currently accepted medical use, and lack of accepted safety for use under medical supervision. This classification applies to marijuana-derived CBD regardless of THC content, creating legal obstacles for researchers who must obtain DEA registration, maintain extensive security measures, and source material from limited federally-approved suppliers. Hemp-derived CBD occupies a distinct legal category following the Agriculture Improvement Act of 2018 (Farm Bill), which removed hemp containing less than 0.3% delta-9 THC from Schedule I classification. This legislation created a bifurcated CBD market: hemp-derived products sold widely with minimal regulation, and marijuana-derived CBD remaining federally prohibited except for FDA-approved medications. The 0.3% THC threshold derives from a 1976 taxonomic distinction rather than pharmacological evidence, creating arbitrary legal boundaries that complicate research and product development. The FDA maintains authority over CBD products under the Federal Food, Drug, and Cosmetic Act, prohibiting CBD in dietary supplements and food products pending further safety review. The agency's 2019 statement acknowledged CBD's therapeutic potential while expressing concerns about hepatotoxicity, drug interactions, and effects on male reproductive systems observed in animal studies. FDA enforcement has been selective, focusing on companies making explicit disease treatment claims while largely tolerating the broader CBD market. State medical marijuana laws create parallel legal frameworks that enable research within state boundaries. As of 2026, 38 states and the District of Columbia have enacted comprehensive medical cannabis programs, with chronic pain qualifying as an eligible condition in 36 of these jurisdictions. State laws vary substantially in their research provisions, with some states including specific language encouraging academic investigation while others impose restrictions that exceed federal requirements. The Rohrabacher-Farr Amendment, renewed annually since 2014 and codified in federal appropriations bills, prohibits the Department of Justice from using funds to interfere with state medical marijuana programs. This provision has provided practical protection for state-legal research activities, though it does not create affirmative legal authorization for Schedule I research. Institutional review boards at research universities must navigate these overlapping jurisdictions when approving CBD-opioid studies. Protocols must satisfy federal human subjects protections under 45 CFR Part 46, demonstrate scientific merit, and address safety concerns specific to cannabinoid-opioid combinations including potential for enhanced sedation, respiratory depression, and cognitive impairment.

State-by-State Medical Cannabis Research Landscape

State-level policies significantly influence the feasibility and scope of CBD-opioid research, with some jurisdictions actively promoting investigation while others maintain restrictive frameworks.

California

California established the Center for Medicinal Cannabis Research in 2000 through Senate Bill 847, appropriating $3 million annually for clinical research. The state's medical marijuana program, operational since 1996 under Proposition 215, allows physicians to recommend cannabis for any condition for which it provides relief. California researchers have published more peer-reviewed cannabis studies than any other state, with multiple trials examining cannabis-opioid interactions in chronic pain populations. The state's Adult Use of Marijuana Act (Proposition 64, 2016) allocated tax revenue for continued research funding, though appropriations have fallen short of initial projections.

Colorado

Colorado's medical marijuana program, authorized by Amendment 20 in 2000, includes chronic pain as a qualifying condition. The state has not established a dedicated research center but provides regulatory pathways for academic institutions to conduct clinical trials using state-licensed cannabis. Researchers at the University of Colorado have leveraged these provisions to study CBD-opioid interactions, though federal restrictions on transporting cannabis across state lines limit collaboration with out-of-state institutions.

Florida

Florida's medical marijuana program, established through Amendment 2 in 2016, requires the state Department of Health to license medical marijuana treatment centers to conduct research. The law specifically encourages investigation of cannabis for opioid use disorder and chronic pain. However, implementation has been slow, with only limited research protocols approved as of 2026. Florida's program prohibits smokable marijuana flower except for qualified patients, complicating research designs that examine various administration routes.

Massachusetts

Massachusetts legalized medical marijuana through ballot initiative in 2012, with regulations taking effect in 2013. The state's Cannabis Control Commission has authority to approve research licenses, and several academic medical centers including Massachusetts General Hospital have initiated cannabis research programs. The state's opioid crisis severity—with overdose rates 50% above the national average in 2020—has driven particular interest in cannabis-opioid research, with state funding allocated for harm reduction studies.

New York

New York's medical marijuana program, established through the Compassionate Care Act in 2014 and significantly expanded in 2016, initially restricted research to state-registered organizations. The 2021 Marijuana Regulation and Taxation Act broadened research access and allocated funding for studies examining cannabis as an opioid alternative. New York permits only non-smokable cannabis formulations in its medical program, focusing research on tinctures, capsules, and vaporizable oils that may be more suitable for controlled clinical trials.

Ohio

Ohio legalized medical marijuana through House Bill 523 in 2016, with the program becoming operational in 2019. The law includes provisions for research licenses and identifies chronic pain as a qualifying condition. However, Ohio's program has faced implementation challenges including limited dispensary access and high product costs that have constrained patient enrollment and research recruitment.

Pennsylvania

Pennsylvania's Medical Marijuana Act, signed in 2016, established one of the nation's most comprehensive medical cannabis programs with explicit research provisions. The law created a medical marijuana research program at eight academic clinical research centers, with $2 million in initial funding. Research priorities include opioid use disorder and chronic pain, with several ongoing studies examining CBD-opioid interactions in post-surgical pain management.

Market and Business Implications

Validated CBD-opioid interaction research could reshape multiple sectors including pharmaceutical development, medical cannabis operations, pain management clinics, and health insurance coverage policies. The pharmaceutical industry faces both opportunity and disruption. If CBD demonstrates clinically significant opioid-sparing effects in large-scale trials, drug manufacturers could develop combination products pairing CBD with existing opioid medications. Such products would require FDA approval through the new drug application process, involving Phase I-III clinical trials costing $100-300 million and requiring 7-10 years from initial development to market authorization. Patent strategies would be complex, as CBD itself cannot be patented but specific formulations, delivery systems, and combination ratios may qualify for intellectual property protection. Generic opioid manufacturers could face market pressure if CBD-opioid combinations demonstrate superior safety profiles. The generic opioid market generated $4.2 billion in U.S. sales in 2023, with products including oxycodone, hydrocodone, and morphine facing potential displacement by novel combination therapies. Conversely, generic manufacturers might partner with CBD producers to develop their own combination products as patents expire. Multi-state operators in the cannabis industry are positioning for potential pharmaceutical partnerships or independent product development. Companies including Curaleaf, Trulieve, and Green Thumb Industries have established pharmaceutical-grade manufacturing capabilities and clinical research partnerships. The medical cannabis market generated $11.4 billion in sales in 2023, with pain management products representing the largest category. Validated research demonstrating CBD's opioid-sparing effects could expand medical cannabis patient populations and strengthen reimbursement arguments with health insurers. Pain management clinics represent a critical adoption pathway. The American Academy of Pain Medicine estimates 7,000 pain management physicians practice in the United States, serving millions of chronic pain patients. Clinical guidelines from specialty societies increasingly acknowledge cannabis as a potential treatment option, though most stop short of strong recommendations due to limited high-quality evidence. Robust CBD-opioid research could shift clinical practice patterns, with pain specialists incorporating CBD into multimodal pain management protocols. Health insurance coverage remains a significant barrier and opportunity. Medicare and Medicaid cannot cover Schedule I substances under federal law, excluding marijuana-derived CBD from reimbursement even in states with medical marijuana programs. Private insurers have largely declined to cover medical cannabis, citing federal illegality and insufficient evidence. However, FDA-approved CBD medications like Epidiolex receive insurance coverage, establishing precedent that could extend to future CBD-opioid combination products approved through formal regulatory pathways. The economic implications for opioid-dependent communities are substantial. States with high opioid prescribing rates and overdose mortality could see healthcare cost reductions if CBD-opioid combinations reduce adverse events. A 2021 analysis in Health Affairs estimated that medical cannabis access was associated with $1.2 billion in annual Medicare savings through reduced opioid prescribing. Expanded CBD-opioid research could amplify these effects while creating new economic activity in cannabis cultivation, processing, and distribution.

What Experts Say

Scientific and clinical experts express cautious optimism about CBD-opioid research while emphasizing the need for rigorous clinical trials and careful attention to safety concerns. Researchers at the University of California, San Diego who have conducted multiple cannabis-opioid studies note that preclinical and early human data suggest synergistic analgesic effects, but emphasize that optimal dosing ratios, administration timing, and patient selection criteria remain unclear. According to their published research, cannabis appears to enhance opioid analgesia at low to moderate doses, but this enhancement may plateau or reverse at higher doses, creating a narrow therapeutic window that requires careful clinical management. Pain medicine specialists at Johns Hopkins University have described CBD as a potentially valuable tool in multimodal pain management, particularly for patients who have achieved inadequate relief from opioids alone or who experience dose-limiting side effects. Their clinical experience suggests that some patients can reduce opioid doses by 30-50% when adding CBD to their regimen while maintaining or improving pain control, though individual responses vary considerably. Addiction medicine experts have highlighted CBD's potential role in addressing opioid use disorder, distinct from its pain management applications. Research published by investigators at the Icahn School of Medicine at Mount Sinai demonstrated that CBD reduced cue-induced craving and anxiety in individuals with heroin use disorder, suggesting mechanisms beyond simple analgesic enhancement. These researchers emphasize that CBD does not produce euphoria or have significant abuse potential, making it a safer adjunct than other psychoactive substances. Pharmacologists have raised important safety considerations regarding CBD-opioid combinations. CBD inhibits several cytochrome P450 enzymes including CYP3A4 and CYP2D6, which metabolize many opioid medications. This inhibition could increase opioid blood levels and duration of action, potentially enhancing both therapeutic effects and adverse events including respiratory depression. Experts stress the need for pharmacokinetic studies to characterize these interactions and establish safe dosing guidelines. Regulatory scientists at the FDA have acknowledged CBD's therapeutic potential while maintaining that rigorous clinical trials are essential before widespread clinical adoption. The agency's position, articulated in public statements and guidance documents, is that CBD-opioid combinations must demonstrate safety and efficacy through controlled trials meeting the same evidentiary standards applied to conventional pharmaceuticals. Patient advocacy organizations have emphasized that many chronic pain patients are already combining CBD and opioids based on anecdotal reports and limited evidence, often without physician guidance. These organizations argue that accelerated research is necessary to provide evidence-based recommendations and prevent potential harms from unmonitored self-medication.

What's Next

The trajectory of CBD-opioid research over the next 3-5 years will be shaped by ongoing clinical trials, regulatory decisions, and potential federal cannabis policy reforms. Several large-scale clinical trials are currently recruiting or in progress. A Phase II trial at the University of California, San Francisco is examining CBD as an adjunct to buprenorphine for chronic pain management in patients with opioid use disorder, with results expected in late 2027. The study will assess whether CBD allows for lower buprenorphine doses while maintaining pain control and reducing opioid craving. A separate multicenter trial coordinated by Johns Hopkins University is evaluating CBD-oxycodone combinations for post-surgical pain, with primary endpoints including opioid consumption, pain scores, and adverse events over a 14-day post-operative period. Federal policy developments could significantly accelerate research. The Cannabis Administration and Opportunity Act, reintroduced in Congress in 2025, would remove marijuana from Schedule I and transfer regulatory authority from the DEA to the FDA and Alcohol and Tobacco Tax and Trade Bureau. If enacted, this legislation would eliminate major barriers to cannabis research including DEA registration requirements and restrictions on interstate transport of research materials. However, the bill faces uncertain prospects in a divided Congress. The DEA's potential rescheduling of marijuana to Schedule III, under consideration following a 2023 recommendation from the Department of Health and Human Services, would maintain federal control while acknowledging accepted medical use. Schedule III classification would ease research access and allow physicians to prescribe marijuana-derived medications, though it would not legalize recreational use or eliminate all research barriers. State-level developments will continue to shape the research landscape. Several states including Minnesota, Connecticut, and Maryland have recently allocated funding for cannabis research with specific emphasis on opioid-related applications. These state initiatives may generate preliminary data that informs larger federal studies and clinical practice guidelines. Industry developments to monitor include pharmaceutical company pipeline announcements, FDA guidance updates on cannabis-derived drug development, and potential partnerships between cannabis companies and traditional pharmaceutical manufacturers. The first FDA approval of a CBD-opioid combination product, if it occurs, would establish regulatory precedent and likely trigger substantial investment in similar product development. Clinical practice guideline updates from organizations including the American Academy of Pain Medicine, American Society of Addiction Medicine, and American Medical Association will reflect evolving evidence. Current guidelines generally acknowledge cannabis as a potential treatment option while noting evidence limitations. Robust clinical trial results could shift these recommendations toward more definitive support for CBD-opioid combinations in specific clinical contexts. Key decision points and dates include:

• Late 2026: Expected publication of additional preclinical studies examining CBD-opioid synergy mechanisms
• Q2 2027: Anticipated results from UCSF Phase II trial of CBD with buprenorphine
• Q4 2027: Johns Hopkins multicenter post-surgical pain trial completion
• 2027-2028: Potential DEA final rule on marijuana rescheduling
• 2028: Possible FDA guidance update on cannabis-derived drug development
• 2029-2030: Earliest realistic timeline for FDA approval of a CBD-opioid combination product, assuming favorable trial results

Further Reading and Primary Sources

• National Institute on Drug Abuse: Cannabis and Cannabinoid Research - https://nida.nih.gov/research-topics/marijuana
• FDA Regulation of Cannabis and Cannabis-Derived Products - https://www.fda.gov/news-events/public-health-focus/fda-regulation-cannabis-and-cannabis-derived-products
• University of California Center for Medicinal Cannabis Research - https://cmcr.ucsd.edu/
• Controlled Substances Act, 21 U.S.C. § 812 - https://www.deadiversion.usdoj.gov/21cfr/21usc/812.htm
• Agriculture Improvement Act of 2018 (Farm Bill), Public Law 115-334 - https://www.congress.gov/bill/115th-congress/house-bill/2
• Americans for Safe Access Medical Cannabis Research - https://www.safeaccessnowresearch.org/
• Centers for Disease Control and Prevention: Opioid Data Analysis and Resources - https://www.cdc.gov/opioids/data/index.html
• Journal of Pain: Cannabis-Opioid Interaction Studies Archive - https://www.jpain.org/
• National Academies of Sciences, Engineering, and Medicine: The Health Effects of Cannabis and Cannabinoids (2017) - https://www.nap.edu/catalog/24625/
• DEA Diversion Control Division: Controlled Substance Schedules - https://www.deadiversion.usdoj.gov/schedules/