Data shows medical marijuana use decreased in states where recreational use became legal 

Number of patients using cannabis for medical purposes has increased more than 600 percent since 2016

2:35 PM

Author | Kelly Malcom

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Credit: Justine Ross, Jacob Dwyer/Michigan Medicine

The most recent data on medical cannabis use found that enrollment in medical cannabis programs increased overall between 2016 and 2022, but enrollment in states where nonmedical use of cannabis became legal saw a decrease in enrollment. 

Combined with the data from a previously published analysis, the number of patients using cannabis for medical purposes has increased more than 600 percent since 2016. The study is published in Annals of Internal Medicine.  

“These findings indicate the growing use of cannabis for medical purposes, but also that adult use laws may decrease rates of patient enrollment,” said Kevin Boehnke, Ph.D., a research assistant professor in the U-M Medical School Department of Anesthesiology and Chronic Pain & Fatigue Research Center.

Cannabis is legal for medical or nonmedical use in 38 and 23 states, respectively. However, it remains a schedule I substance under the Controlled Substances Act. This status has inhibited research on its health effects and disincentivized many physicians from pursuing education related to or treating patients who use cannabis. Recently, the Department of Health and Human Services recommended that cannabis be rescheduled to schedule III. Before this potential shift occurs, it is important to understand the current landscape of medical and nonmedical cannabis use and authorization.  

Researchers from University of Michigan Medical School and the Centers for Disease Control and Prevention conducted an ecological study with repeated measures of persons with medical cannabis licenses and clinicians authorizing cannabis licenses in the United States between 2020 and 2022. 

The authors included 39 jurisdictions (38 states and Washington, D.C.) that allowed for medical cannabis use in their analysis. Of these jurisdictions, 34 reported patient numbers, 19 reported patient-reported qualifying conditions, and 29 reported authorizing clinician numbers. They reported a 33 percent increase in enrollment in these jurisdictions between 2020 and 2022. 

The authors also included 15 jurisdictions with nonmedical adult-use laws. They found that in 13 of these 15 jurisdictions, medical enrollment decreased, and the proportion of patient-reported qualifying conditions with substantial or conclusive evidence of therapeutic value decreased from 70.4 to 53.8 percent. The most reported qualifying condition was chronic pain, followed by anxiety and post-traumatic stress disorder. 

The team notes that their findings highlight the need for better surveillance methods to adequately understand outcomes of medical cannabis use and thoughtful strategies and public health efforts to reduce harms from increased cannabis availability. 

A three-pronged radar graph visualization with spokes made of marijuana leaves with their lengths corresponding to total use volume data. Underneath the leaves are three lines depicting the prescriber volumes. The years 2020 - 2022 are shown from left to right. Text reads, “Overall, both total medical user and prescriber volumes grew from 2020 - 2022.”

 

Small multiples of the same leaf and root visualization as first image showing state-level data, with groups of four different scales (10,000, 15,000, 30,000 and 200,000) to accommodate for disparate data values. The state-level root scale is from 0 to 5,300. Text reads, “Trends varied across each state during the 3 year period.”

 

Streamgraph in shades of purple and green, depicting the overall growth in the number of registered medical cannabis users in medical use-only states. Text reads, “In states without legal recreational cannabis that reported data during the study period, the number of registered medical users grew overall.”

 

Streamgraph in shades of purple and green, depicting the overall decrease in the number of registered medical cannabis users in states where recreational marijuana use is legalized. Text reads, “By contrast, in states with legalized recreational cannabis, the number of registered medical users decreased.”

 

Legend for the “Visualizing Medical Cannabis Use & Prescriber Trends 2020 - 2022 data visualizations. This includes radar graph and line graph scales, and the visual key for line thickness and graphic elements for small multiples of state-level data.

 

Additional authors: Rachel Sinclair, B.Sc., Felicia Gordon, B.Sc., Avinash Hosanagar, M.D., Douglas R. Roehler, Ph.D., Tristin Smith, M.P.H., and Brooke Hoots, Ph.D.

Citation:Trends in U.S. Medical Cannabis Registrations, Authorizing Clinicians, and Reasons for Use From 2020 to 2022”. Annals of Internal Medicine, DOI: 10.7326/M23-28

Reposted from Annals of Internal Medicine

Data visualization credits: Data Source, “Trends in U.S. Medical Cannabis Registrations, Authorizing Clinicians, and Reasons for Use From 2020 to 2022”. Annals of Internal Medicine, DOI: 10.7326/M23-28. Data Visualization Created Using RawGraphs and Adobe Illustrator. Leaf Source Image Credit: Getty Images. Design Assistance: Jacob Dwyer, Justine Ross, Michigan Medicine. Data Visualizations by Elizabeth Palmer Jarvis, Michigan Medicine.

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