What impact does the availability of legal cannabis have on health outcomes?

By Bhavana KunkalikarReviewed by Lily Ramsey, LLMMay 2 2023

In a recent study published in the International Journal of Drug Policy, researchers explored the relationship between the availability of legal cannabis and its impact on cannabis usage and health outcomes.

Study: The impact of legal cannabis availability on cannabis use and health outcomes: A systematic review. Image Credit: OMfotovideocontent/Shutterstock.com

Background

Legalizing cannabis for medical activities has increased the availability of medical cannabis outlets, linked to increased consumption and hospitalizations related to cannabis use disorder.

Notably, the differences in medical and recreational markets impact these hospitalizations. Reports from the recreational market are crucial for shaping present and future legislative processes.

About the study

In the present study, researchers reported behavioral outcomes, such as cannabis purchases, intake, risky use trends, and cannabis-associated health indicators.

In the Summer of 2022, a systematic literature review was conducted on different elements of the legal cannabis markets, such as availability, sales, and health warning labels. The authors searched for studies investigating the relationship between cannabis availability and harm using specific search terms, such as availability, outlet, density, retail, store, license, and monopoly. Five authors initially screened only the titles and abstracts to complete the search.

Studies published in English, Spanish, and German since 2012 were reviewed. The studies included subjects from different groups, such as the general population, cannabis users, those affected by others' cannabis use, and other target groups. These groups were chosen to explore various regulatory options.

The studies were categorized based on their design and then summarized in a narrative format. The results were categorized based on various availability indicators, if relevant.

The team extracted significant findings related to dose-response correlations between availability and three outcome types, including current usage, risky usage, and health indicators or categorical analyses that identify the groups most impacted by high availability.

Results

Of 6,253 studies, 136 were selected for full-text screening after removing duplicates. Almost 50% of the studies included data on any form of legalization. The studies examined the correlation between legal cannabis and measures of cannabis utilization and health outcomes. Various availability indicators were used in the studies, classified as density or proximity estimates.

Proximity measures typically indicate the distance between respondents and the closest cannabis retailer. The proximity measure is determined by combining zip code information or personal addresses with the location data of cannabis retailers. Proximity measures are often presented in kilometers or miles or as the driving time needed to reach the nearest retailer.

The first study found a correlation between the proximity of cannabis retailers to schools or school districts concerning cannabis use indicators among a group of school students.

The study found that eleventh-grade students who attended schools within one mile of a cannabis retailer had a higher prevalence of dabbed cannabis, smoked cannabis usage, and edible consumption.

However, there was no significant relationship for eighth-grade students. A survey of youth aged between 14- and 18 years in US states with a minimum of one retailer per 100,000 population exhibited a higher occurrence of lifetime cannabis vaping.

Furthermore, a study showed that individuals residing in US states with fewer than one retailer were less likely to have used edibles in their lifetime compared to those living in US states having no retailers.

Two studies analyzed data from a school student survey to investigate the correlation between alcohol and cannabis and the density of legal cannabis retailers. The first study found a higher prevalence of cannabis usage among students in counties with more cannabis retailers.

The association was significant even after adjusting for perceived cannabis availability. The co-use of alcohol and cannabis was significantly associated with the density of cannabis and alcohol retailers as per the second study.

Another study analyzed the correlation between the density of cannabis retailers and county-level quarterly information derived from hospitals or emergency departments located in Colorado, USA.

Counties with more cannabis retailers tend to have more emergency department visits for vomiting, psychosis, and hospitalizations related to cannabis use during pregnancy. The density of cannabis retailers at the county level did not show a significant relationship with emergency department visits related to schizophrenia.

Conclusion

The study findings showed that the recreational cannabis market legalization is expected to lead to a rise in cannabis availability. Cannabis availability may lead to more consumption and health risks, particularly among those who consume it less frequently. Curbing the number of licenses may be considered in legalized cannabis markets to restrict geographical access.