The odds that a patient visiting the emergency department is diagnosed with cannabis use disorder (CUD) is nearly 50 percent lower in states that have legalized marijuana compared to non-legal states, according to a new study. And researchers say the “counterintuitive” finding could be related to the destigmatization of cannabis use within the medical community as prohibition ends.
The study, published in the journal Preventative Medicine Reports last week, looked at emergency department data from 2017 to 2020 in two states that had legalized cannabis (Colorado and Oregon) and two states where it was prohibited at the time of the review (Maryland and Rhode Island).
Specifically, they examined rates of “treat and release” visits where patients received a CUD diagnosis indicating problematic marijuana use. Researchers used a multivariate logistic regression model to analyze a total of 17,434,655 emergency room visits over the four-year period.
The study authors said they expected to see higher rates of CUD in recreational cannabis states given that past studies have found that legalization is associated with slightly increased rates of marijuana use among adults. But the data showed the opposite: “Compared to states where recreational cannabis was illegal, legalizing cannabis for recreational use was associated with nearly a 50 percent decrease in the adjusted odds of CUD.”
“Our findings, which demonstrate lower rates of CUD in states that enacted and implemented recreational cannabis laws (CO and OR) compared to those that did not (MD, and RI), could inform policymakers’ actions—i.e., recreational cannabis laws may not place public health and safety at risk,” they said, “however, given the counterintuitive nature of our findings, we recommend additional research and exploration of the CUD-legalization relationship be pursued in EDs and other care settings.”
Prior research on post-legalization hospitalizations and emergency department visits has largely focused on youth, which means even marginal changes could appear more pronounced given the relatively low rate of cannabis use within that population, the researchers said.
There have been some studies linking legalization to increased rates of CUD diagnoses in publicly funded substance misuse treatment facilities (while others have determined that forced treatment referrals declined faster after the reform is enacted). In any case, the authors of this latest research say it’s the “first study to find evidence of this same negative, statistically significant association between the legalization of recreational cannabis and CUD among ED visits.”
“What might predict this relationship? The researchers who have found declining CUD admissions to substance use disorder treatment programs following legalization have hypothesized that decreased stigma and increased social acceptability of cannabis use may explain their findings,” the study says.
“If, in states that have legalized cannabis, providers are more tolerant of cannabis use and less likely to recognize problematic behavior associated with CUD (e.g., persistent or recurrent social or interpersonal problems, cravings, withdrawal), they may be less likely to diagnose and document CUD in the medical record,” the authors continued. “This could account for lower CUD prevalence in the ED in legalized states.”
They added that if the findings are valid, “policymakers could continue to pass recreational cannabis laws—for all the reasons states are enacting such legislation—without risking the public health and/or safety of ‘treat and release’ ED patients.”
This builds on the scientific literature surrounding CUD, and it’s one of the latest examples to challenge legalization opponents’ arguments that legalization would lead to increased public health problems such as higher rates of problematic marijuana use. A 2019 study separately found the rates of CUD have decreased amid the state-level legalization movement.
Meanwhile, a growing body of research—including a study published by the American Medical Association (AMA) in September—has found that youth cannabis use has actually been decreasing as more states have moved to replace prohibition with systems of regulated recreational sales for adults.
A separate National Institute on Drug Abuse-funded study published in the American Journal of Preventive Medicine last year also found that state-level cannabis legalization is not associated with increased youth use. That study observed that “youth who spent more of their adolescence under legalization were no more or less likely to have used cannabis at age 15 years than adolescents who spent little or no time under legalization.”
Yet another federally funded study from Michigan State University that was published in the journal PLOS One last year found that “cannabis retail sales might be followed by the increased occurrence of cannabis onsets for older adults” in legal states, “but not for underage persons who cannot buy cannabis products in a retail outlet.” (Full Story)