Study: Demand for codeine drops when cannabis is legalized

A new study conducted by researchers at Cornell University, the University of Pittsburgh, the University of Georgia and George Mason University has revealed that American states that have legalized cannabis are seeing a reduction in the demand for prescription codeine.

The study, published in Health Economics, reports a 26 % reduction in codeine dispensing in pharmacies, and a reduction of up to 37 % after adult-use cannabis laws had been in effect for four years.

The researchers note that cannabis laws for adults have had minimal impact on codeine dispensing by hospitals, which often have less permissive policies than pharmacies, and minimal impact on the dispensing of other opioids such as oxycodone, hydrocodone and morphine, whatever the context.

Coleman Drake, of the University of Pittsburgh School of Public Health and lead author of the study, called the findings «particularly significant» because «previous studies have focused on more potent opioids».

«Codeine is a weaker drug with a higher addiction potential. This indicates that people can obtain codeine from pharmacies for misuse, and that recreational cannabis laws reduce this illicit demand.» explained Drake.

Johanna Catherine Maclean, of George Mason University and author of the study, said the research suggests that «increasing legal access to cannabis may divert some consumers from opioids and steer them towards cannabis.»

«While all substances present certain risks,» she said in a statement, «cannabis use is arguably less harmful to health than the non-medical use of prescription opioids.»

The researchers analyzed data from the Drug Enforcement Administration, which tracks the flow of controlled substances in the United States.

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