United States healthcare encounters for poisoning involving cannabis relative to other substances

<i>Background:</i> Despite increases in cannabis-related healthcare encounters, research comparing trends in healthcare encounters involving cannabis poisoning with other substances is limited.<i>Objective:</i> To describe healthcare encounters (emergency department [ED] visits and hospitalizations) for poisonings involving cannabis versus other substances (heroin, cocaine, benzodiazepines, alcohol).<i>Methods:</i> We used cross-sectional data from the Nationwide Emergency Department Sample, the National Inpatient Sample (2016-2020), and the National Survey on Drug Use and Health to estimate annual national encounters involving poisoning and utilization-adjusted prevalence per 100,000 individuals reporting past-year use of that substance.<i>Results:</i> From 2016 to 2020, encounters involving cannabis poisoning were lower than heroin and benzodiazepines, and utilization-adjusted prevalence was lower than heroin, cocaine, and benzodiazepines. U.S. cannabis poisoning ED visits (2016: 29,050; 2019: 49,357; 2020: 47,655) and hospitalizations (2016: 12,940; 2019: 18,470; 2020: 13,680) increased between 2016 and 2019, and decreased in 2020, whereas most other substances decreased. Utilization-adjusted prevalence of cannabis poisoning ED visits (2016: 77.3 [95%CI, 70.3-84.3]; 2019: 102.0 [95%CI, 94.7-109.2]; 2020: 98.5 [95%CI, 91.0-106.0]) and hospitalizations (2016: 34.4 [95%CI, 32.6-36.3]; 2019: 38.2 [95%CI, 36.4-39.9]; 2020: 28.3 [95%CI, 26.9-29.7]) followed the same pattern, whereas most other substances declined. In 2020, utilization-adjusted prevalence of transfer/hospital admission was lower for single-substance ED visits involving cannabis poisoning than most other substances. Deaths were higher in single-substance hospitalizations for other substances than cannabis in 2020.<i>Conclusions:</i> Healthcare encounters involving cannabis poisoning increased while remaining lower, and having fewer admissions/deaths, than selected, other substances. These findings can inform healthcare policy and prevention strategies for cannabis-related healthcare encounters.