Study links legal cannabis access with reduced opioid use in cancer patients.
A large national study has found that when cannabis dispensaries open, opioid prescriptions for people with cancer tend to drop. The findings suggest that greater access to cannabis could be influencing both patient choices and doctor prescribing habits, causing this drop, especially in states where medical or recreational cannabis is legal.
The study, conducted by researchers at the University of Georgia and published in JAMA Health Forum, examined prescription data from more than three million adults with cancer across the United States between 2007 and 2020. The researchers focused on people with commercial insurance and at least one opioid prescription. They compared opioid prescribing patterns in states before and after the opening of cannabis dispensaries, both medical and recreational.
After cannabis dispensaries opened, three different measures of opioid use declined noticeably. Fewer people received opioid prescriptions, the number of prescriptions per person dropped, and the average days’ supply per prescription decreased. These reductions were greater in states with medical cannabis access than in those that legalized recreational use.
Lead researcher and nurse scientist Victoria Bethel said the results point to a potential substitution effect. In other words, some patients may be replacing opioids with cannabis for pain relief. Bethel noted that patients with cancer often need strong pain management options, but opioids carry serious risks such as tolerance, dependence, and side effects like nausea or confusion. For some, cannabis may offer partial relief without the same level of danger. Still, she emphasized that more studies are needed to fully understand both the benefits and harms of cannabis for pain.
Opioids remain the standard treatment for severe cancer-related pain, but their use has long raised concerns. In addition to addiction risks, long-term opioid use can cause sleep problems, mood changes, and digestive issues. The possibility that cannabis could fill some of that role has led to growing interest among both patients and clinicians.
Currently, 39 states and the District of Columbia allow medical cannabis, and nearly half of all U.S. states also permit recreational use. Cannabis products and synthetic cannabinoids have been used for years to treat chemotherapy side effects such as nausea and appetite loss, but solid evidence for pain management has been harder to come by.
While a few trials have shown that medical cannabis may help lower pain scores, others found only limited results or unwanted side effects such as dizziness and mild hallucinations. Bethel’s team sought to fill that research gap by examining whether state-level legalization made a measurable difference in real-world opioid use. The drop in prescribing rates that followed dispensary openings suggests that cannabis availability could be shifting how pain is managed for many cancer patients.
The researchers acknowledged that while the drop in opioid use seems positive, their study has limits. They used data from commercially insured patients, which means the results might not apply to people covered by Medicaid or Medicare. Other new laws passed around the same time as cannabis legislation may also have influenced prescribing trends. Despite these caveats, the link between cannabis access and reduced opioid use remains strong enough to warrant attention from policymakers and clinicians.
The growing popularity of cannabis raises another concern: accidental exposure among children. A separate study from the same research team found that the opening of medical dispensaries was followed by a sharp increase in cannabis-related poison calls involving young children. That finding points to the importance of education, child safety packaging, and careful regulation even as states move to expand legal access.
Experts stress that open communication between patients and providers is key. Patients may be more willing to disclose cannabis use when they feel safe from judgment, which helps doctors make informed decisions and avoid dangerous drug combinations. Bethel said the long-term goal should be to build a healthcare environment where research, honesty, and safety can all coexist as cannabis becomes a more common part of pain management.
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