CBD Access, Not Legalization Alone, Was Linked to Lower Opioid Prescribing in a 2024 Study
A 2024 study found that state laws allowing limited access to cannabidiol (CBD) products were not, by themselves, associated with lower opioid prescribing. The reduction appeared only when people could obtain CBD through legal, relatively open retail channels.
In the study published in the Southern Economic Journal, economists Tim Bersak, Richard Gearhart and Nyakundi Michieka examined county-level opioid prescribing rates from 2010 through 2019, along with state-level consumption of eight commonly prescribed opioids measured in morphine milligram equivalents.
The researchers distinguished between laws that technically permitted certain CBD products and policies that made those products available in practice. Their analysis found no measurable change in opioid prescribing after states adopted limited-access, CBD-only laws. By contrast, measures of legal supply-side access—including legal, open dispensaries and the ability to purchase products across state lines—were associated with 6.6% to 8.1% fewer opioid prescriptions relative to pre-legalization averages.
A synthetic-control analysis produced a smaller estimate: states with legal and open dispensaries had opioid prescribing rates nearly 3.5% lower two years after legalization. The findings suggest that legal recognition alone may have little effect if patients cannot readily obtain the products covered by the law.
Restrictions appeared to weaken the association
The study also examined rules that made CBD purchases more difficult, including identification requirements and patient registries. The authors reported that these restrictions offset most of the apparent benefit associated with legal access.
That result does not show that CBD directly caused patients to stop using opioids. The research used state and county policy data rather than randomized treatment assignments, so it cannot establish that individuals replaced opioid medications with CBD. Other changes occurring during the same period—including tighter opioid-prescribing policies, shifts in medical practice and changes in the illicit drug market—could also have affected prescribing rates.
The study therefore offers evidence about the relationship between policy design and prescribing patterns, not proof that CBD is an effective substitute for opioid pain medication.
CBD laws varied widely during the study period
The analysis focused on limited-access cannabis-product laws adopted between 2010 and 2019. These measures generally allowed qualifying patients with specified medical conditions to obtain low-THC or CBD-focused products. They differed substantially in eligibility rules, product availability, dispensary protections, registration requirements and purchase restrictions.
That variation is important. A law may authorize a product on paper without creating a functioning market in which patients can legally and consistently obtain it. The researchers argued that future evaluations should measure actual access—including whether dispensaries are open and whether consumers can purchase products without burdensome administrative requirements—rather than treating every legalization law as equivalent.
What the findings do—and do not—say about CBD
CBD is a non-intoxicating compound found in cannabis, but state-legal CBD products are not necessarily standardized medicines. The U.S. Food and Drug Administration says that it has approved one CBD drug, Epidiolex, for certain severe seizure disorders. Other widely sold CBD products have not been FDA-approved to treat pain or reduce opioid use, and their dosage, purity, drug interactions and long-term safety may vary.
Research on cannabis and pain is broader than research on CBD alone. A National Academies review found substantial evidence that some cannabis or cannabinoid products can provide modest relief for chronic pain in adults, while also noting that the evidence does not necessarily apply to the wide range of products sold in commercial markets. A broader review of state cannabis-law research has likewise found inconsistent results for opioid prescribing and other opioid-related outcomes.
The economists described their results as preliminary and called for additional research, particularly studies that can connect policy changes with individual-level treatment decisions. For policymakers, the central implication is narrower than the original headline suggested: if CBD access is pursued as one component of pain-management policy, the effects may depend on whether products are actually available, how access is regulated and whether quality and safety can be reliably monitored.
