Opioid Deaths Fall When Cannabis Stores Rise, Analysis Suggests

Can legal marijuana ease the opioid crisis?

https://www.medpagetoday.com/neurology/opioids/90922

Access to legal cannabis stores was linked with fewer opioid deaths in the U.S., a new analysis suggested.

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

This means that increasing the number of storefront dispensaries from one to two was tied to a 17% reduction in death rates of all opioid types, and an increase from two to three stores was associated with a further 8.5% reduction in mortality, Kovács and Hsu noted.

The relationship was stronger — leading to an estimated 21% drop in mortality — when only deaths from synthetic non-methadone opioids like fentanyl were considered (β -0.21, 95% CI -0.27 to -0.14), they wrote in The BMJ.

“We find this relationship holds for both medical dispensaries, which serve only patients who have a state-approved medical card or doctor’s recommendation, as well as for recreational dispensaries, which sell to adults 21 years and older,” Kovács said.

As business school researchers, Kovács and Hsu first became interested in the increasing prevalence of legal cannabis stores as an organizational issue.

“We tracked evolving cannabis markets across the U.S. from 2014 onwards in an effort to understand how this new category of organizations emerged,” Kovács told MedPage Today. “We realized, however, that our county-level database could also be used to examine whether the availability of legal cannabis in an increasing number of geographic areas has any implications for opioid misuse.”

Their findings add to a mixed evidence base about the relationship between legal marijuana and opioid overdoses. In 2014, an analysis suggested that states with medical cannabis laws experienced slower increases in opioid overdose mortality. However, a subsequent study showed that those findings didn’t hold over a longer period, and that associations between state medical cannabis laws and opioid-related mortality reversed direction and remained positive after accounting for 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 2014-2018 CDC mortality data with census data and storefront information from Weedmaps, collecting data on dispensaries operating within each county on a monthly basis from 2014 to December 2017. Mortality analysis focused on deaths of people 21 and older.

Eight states and the District of Columbia allowed for recreational storefronts; 15 allowed for medical dispensaries only. An increase from one to two medical dispensaries led to an estimated 15% mortality rate reduction in the study; an increase from one to two recreational dispensaries led to an 11% drop.

Two points about this analysis need to be considered, noted Sameer Imtiaz, PhD, of the Institute for Mental Health Policy Research in Toronto, and colleagues, in an accompanying editorial.

First, the mechanism underlying the association is unclear. “In the context of medicinal cannabis legalization, reduced deaths from opioid overdose do not coincide with reduced non-medicinal use of pain relievers or with opioid distribution, defined as the flow of substances from the manufacturers to retail distributors,” they wrote. “The absence of concurrent changes in such opioid-related outcomes questions the premise of substitution.”

Moreover, inferences about individuals cannot be drawn from aggregate-level data in an ecologically designed study like this, the editorialists pointed out. Both harmful and beneficial associations between opioids and cannabis have been seen at the individual level, they observed.

The findings suggest a potential relationship between the increased prevalence of cannabis dispensaries and reduced opioid-related mortality and do not show causality, Kovács emphasized. “While we find a particularly strong association between the prevalence of storefront dispensaries and fentanyl-related opioid deaths, it is not clear whether cannabis use and fentanyl mortality rates are more specifically linked, or if the strength of the association is due to the rise in fentanyl use and mortality rates during the study period,” he said. Potential harms of cannabis, including the cognitive development of adolescents, medical conditions such as schizophrenia, and public safety risks, should not be ignored, he added.

Filed under: General Problems