Medical Cannabis Legalization Not Linked With Fewer Opioid Prescriptions, Study Finds
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US states that legalize medical cannabis don’t tend to see a decline in opioid prescriptions for non-cancer pain. That’s the main finding of a new study from researchers at Weill Cornell Medicine.
The team analyzed prescription rates in 12 states with medical cannabis laws and 17 states without them. They found that prescription rates of opioids for chronic pain didn’t significantly differ between the two groups of states.
Across state lines
To make their comparisons, the research team accessed insurance claims, dating between 2010 and 2022, from 29 states, 12 of which (Arkansas, Connecticut, Florida, Louisiana, Maryland, Minnesota, North Dakota, New Hampshire, New York, Oklahoma, Ohio, Pennsylvania) had legal medical cannabis dispensaries, and 17 of which (Alaska, Georgia, Idaho, Indiana, Iowa, Kansas, Kentucky, Mississippi, Nebraska, North Carolina, South Carolina, South Dakota, Tennessee, Texas, Virginia, Wisconsin, Wyoming) didn’t. Some of the 17 states did (and still do), however, have other forms of medical cannabis access, such as legal home cultivation.
From these data, the researchers created 12 distinct comparison groups, one for each medical cannabis law state, that included adults from the 17 comparison states who were continuously enrolled in insurance and met chronic non-cancer pain diagnostic criteria.
They found that medical cannabis laws had an average estimated effect of less than 0.2% on the proportion of patients receiving any opioid prescriptions, non-opioid pain medication prescription, or pain procedure in a given month during the first three years of law implementation.
“Among patients prescribed opioids, average estimated effects of medical cannabis laws on days’ supply and dose were consistently small in magnitude,” the researchers wrote in their paper, which was published in Annals of Internal Medicine.
The researchers say their findings challenge the notion that medical cannabis access might reduce the number of opioid prescriptions in a state, thereby alleviating the ongoing opioid crisis in the US.
“Some research suggests that perhaps medical cannabis laws reduce opioid prescribing for chronic non-cancer pain because some people may substitute cannabis,” Dr. Beth McGinty, chief of the Division of Health Policy and Economics at Weill Cornell Medicine, said in a statement.
“We found no effects of these laws on opioid prescribing or any types of treatment for chronic non-cancer pain that we looked at.”
While McGinty and her colleagues acknowledge that their study has its limitations – they didn’t use any data on medical cannabis prescriptions, for instance – they remain confident in their conclusion.
“It’s an observational study, but we set it up in a way that mimics a clinical trial as closely as possible,” she said.
However, as McGinty noted, other similar observational studies have come to different conclusions. One published in Health Economics earlier this year found that states that legalized recreational cannabis saw a reduction in demand for prescription codeine, an opioid. Another recent study, a survey of 2,183 medical cannabis patients in Florida, found that the majority (90.7%) who had been taking opioids and other pain medications were able to stop taking them or reduce their use after starting their cannabis prescription.