Abstract
BACKGROUND: The unpredictable physiologic and pharmacologic effects of synthetic cannabinoids (SCs) are continuously changing as the chemical structure of SCs evolve to avoid classification as a Schedule I drug under the Controlled Substances Act in the U.S. This results in unpredictable pharmacologic effects and subsequent sequelae. Little is known about national or regional trends of SC clusters. The objective of this study is to investigate trends in SC exposure using emergency department (ED) syndromic data. METHODS: We analyzed ED syndromic data to detect quarterly trends from January 2016 through September 2019 for SC-related exposures within 59 jurisdictions in 47 states by U.S. region. Pearson chi-square tests detected quarter-to-quarter changes and Joinpoint regression assessed trends over time. RESULTS: From January 2016 to September 2019, 21,714 of 303.5 million ED visits involved suspected SC exposures. Nationally, SC-related exposures decreased by 1.9 % (p = .04) on average per quarter, yet exposures increased in the Midwest by 6.3 % (p = .002) and in the Northeast by 3.2 % (p = .03) on average per quarter, and decreased on average per quarter by 7.7% (p ≤ .001) in the Southeast and 11.4 % in the West (p ≤ .001). Known SC exposures that may align with clusters were identified in quarter-to-quarter monitoring. CONCLUSIONS: Only a small proportion of ED visits were related to suspected SC exposure. Although we did identify a small decrease in national SC exposures, there was wide variation by region. Additional efforts are needed to understand variation and to develop prevention and response strategies.