Study: Demand for Codeine Drops When Adult-Use Cannabis Is Legalized

A new study from researchers at Cornell University, the University of Pittsburgh, University of Georgia, and George Mason University found states that have legalized cannabis for adult use see a reduction in demand for prescription codeine. The study, published Thursday in journal Health Economics, found A 26% reduction in pharmacy-based distribution of codeine and as much as a 37% reduction after adult-use cannabis laws have been in effect for four years. 

The researchers note the adult-use cannabis laws had a minimal impact on codeine distribution by hospitals, which often have less permissive policies than pharmacies, and a minimal impact on distribution of other opioids such as oxycodone, hydrocodone, and morphine in any setting. 

Coleman Drake of the University of Pittsburgh’s School of Public Health and the study’s senior author, called the study’s results “particularly meaningful” because “previous studies have focused on more potent opioids.” 

“…Codeine is a weaker drug with a higher potential for addiction. It indicates people may be obtaining codeine from pharmacies for misuse, and that recreational cannabis laws reduce this illicit demand.” — Drake in a statement 

Johanna Catherine Maclean, of George Mason University and author of the study, said the research suggests “Increasing legal access to cannabis may shift some consumers away from opioids and toward cannabis.”  

“While all substances have some risks,” she said in a statement, “cannabis use is arguably less harmful to health than the nonmedical use of prescription opioids.” 

The researchers analyzed data from the Drug Enforcement Administration’s Automation of Reports and Consolidation Orders System which tracks the flow of controlled substances in the U.S.  

The study was supported by the National Institute on Drug Abuse of the National Institutes of Health.