Opioid deaths fall as cannabis stores rise, the analysis suggests


Access to legal cannabis stores has been linked to fewer opioid deaths in the US, according to a new analysis.

The number of marijuana dispensaries in a county was negatively related to the age-adjusted log-transformed opioid mortality rate (β -0.17, 95% CI -0.23 to -0.11), reported Balázs Kovács, PhD, von from Yale University School of Management, New Haven, Connecticut; and Greta Hsu, PhD, from Davis Graduate School of Management, University of California.

This means that increasing the number of pharmacies from one to two was associated with a 17% reduction in the death rate of all opioid types, and increasing the number of pharmacies from two to three was associated with a further 8.5% reduction in mortality, Kovács and Hsu noted.

The relationship was stronger – resulting in an estimated 21% decrease in mortality – when only deaths from synthetic non-methadone opioids such as fentanyl were considered (β -0.21, 95% CI -0.27 to -0, 14), they wrote in The BMJ.

“We find this relationship applies to both medical pharmacies that only serve patients with a government-approved medical card or doctor’s recommendation, and recreational pharmacies that are sold to adults aged 21 and over,” said Kovács.

As researchers at the business school, Kovács and Hsu were initially interested in the increasing spread of legal cannabis stores as an organizational problem.

“We have followed the development of the cannabis markets in the US since 2014 to understand how this new category of organizations came about,” Kovács told MedPage Today. “However, we realized that our county-level database could also be used to examine whether the availability of legal cannabis in an increasing number of geographic areas is having an impact on opioid abuse.”

Their findings complement a mixed evidence base on the relationship between legal marijuana and opioid overdoses. In 2014, an analysis found that states with medical cannabis laws had slower increases in mortality from opioid overdoses. However, a subsequent study showed that these results were not true over time, and that the associations between state medical cannabis laws and opioid-related mortality reversed direction and remained positive after considering recreational cannabis laws.

Kovács and Hsu based their analysis on data from 812 counties in 23 states (plus the District of Columbia) that allowed legal cannabis dispensaries to operate by the end of 2017. They combined CDC mortality data for 2014-2018 with census data and storefront information from Weedmaps. From 2014 to December 2017, data on pharmacies in each county is collected on a monthly basis. The mortality analysis focused on the death of people aged 21 and over.

Eight states and the District of Columbia allowed recreational business; 15 only allowed for medical pharmacies. An increase from one to two medical dispensaries resulted in an estimated 15% reduction in the death rate in the study. An increase from one to two recreational pharmacies resulted in a decrease of 11%.

There are two points to consider about this analysis, noted Sameer Imtiaz, PhD, of the Toronto Mental Health Policy Research Institute and colleagues in an accompanying editorial.

First, the mechanism behind the association is unclear. “In the context of the legalization of medical cannabis, decreased deaths from opioid overdose do not coincide with decreased non-medical pain reliever use or opioid distribution, defined as the flow of substances from manufacturers to retailers,” they wrote. “The lack of concurrent changes in such opioid-related outcomes calls into question the premise of substitution.”

In addition, in such an ecologically designed study, no conclusions about individuals can be drawn from data on an aggregated level, the editors emphasized. They observed that both individual and harmful associations between opioids and cannabis were observed at the individual level.

The results suggest a possible connection between the increased prevalence of cannabis dispensaries and the reduced opioid-related mortality and show no causality, emphasized Kovács. “While we find a particularly strong association between the prevalence of retail outlets and fentanyl-related opioid deaths, it is not clear whether cannabis use and fentanyl death rates are more specifically related, or whether the strength of the association is due to increases in fentanyl use and death rates during Investigation period, “he said. Potential harm from cannabis, including adolescent cognitive development, conditions like schizophrenia, and public safety risks, shouldn’t be ignored, he added.

  • Judy George reports on neurology and neuroscience news for MedPage Today, writing on Brain Aging, Alzheimer’s, Dementia, MS, Rare Diseases, Epilepsy, Autism, Headache, Stroke, Parkinson’s, ALS, Concussion, CTE, Sleep, Pain, and more. consequences


Kovács and Hsu, along with Imtiaz and co-authors, have not disclosed any relevant relationships with industry.