Rosalie Liccardo Pacula
Rosalie Liccardo Pacula, Ph.D. holds the Elizabeth Garrett Chair in Health Policy, Economics & Law in the Health Policy and Management Department at the USC Sol Price School of Public Policy, where she is also currently serving as Chair of the department. Dr. Pacula also co-Chairs the National Academy of Sciences, Engineering and Medicine (NASEM) Forum on Mental Health and Substance Use Disorders and is a Research Associate at the National Bureau of Economic Research. She also serves as the Co-PI on the RAND-USC Schaeffer Opioid Policy Tools and Information Center of Excellence (OPTIC), a P50 Research Center in its 7th year of support from the National Institute on Drug Abuse, which seeks to increase the pace of scientific research that can identify cost-effective strategies for reducing the harms caused by the opioid crisis in different communities.
Session
Significance: Cannabis-related emergency department (A&E) visits are rising, but there has been little research on what underlies this increase. April 20th, a date known for annual counterculture celebrations involving cannabis including its public consumption, provides a unique opportunity to investigate how social influences related to cannabis consumption may contribute to adverse consequences of cannabis.
Objective: To estimate the association between the April 20th date and cannabis-related A&E visit rates across the entire cohort, key sociodemographic groups, and types of A&E visits.
Design, Setting, and Participants: A retrospective analysis of a national sample of United States residents with commercial insurance aged 64 years-old and younger during 2016-2023.
Main Outcomes and Measures: The risk ratio of the number of cannabis-related A&E visits on April 20th to the average of the days exactly one week prior and after (i.e., on April 13th and April 27th) was calculated across the entire sample along with subgroups of age, sex, geographic region, co-occurring health conditions, and state access to open and legally protected dispensaries.
Results: A&E visits for cannabis-related reasons grew from 663 visits per 10,000 enrollees in 2016 to 878 visits per 10,000 enrollees in 2023 (32.4% increase). Across the entire study population, there was a higher likelihood of cannabis-related ED visits (RR 1.17, 95% CI [1.05, 1.31]) on April 20th compared to control dates. In subgroup analyses, this association was largest for 25-35 years olds (RR 1.27, 95% CI [1.02, 1.59], for mental health-related diagnoses (RR 1.24, 95% CI [1.03, 1.48]), and when April 20th fell on a Friday, Saturday, or Sunday (RR 1.31, 95% CI [1.05, 1.63]).
Conclusions: April 20th is associated with a substantially higher risk of cannabis-related A&E visits. Given the nature of this counterculture holiday, further investigations into the social nature of cannabis use may provide insights into what underlies the rising rates of cannabis-related adverse health events.