Cannabis is involved in most substance-related emergency department visits and hospitalizations among teenagers and young adults, while alcohol-related encounters are more common among older adults, according to new research.
“In general, we have seen that cannabis use is trending up and alcohol use is trending down; but until now, we haven’t had high-quality data tracking what kind of use is causing immediate harm — emergency room visits and hospitalizations,” said Dr. Kevin Xu, the study’s lead researcher and an assistant professor of psychiatry at WashU Medicine, in a press release.
Researchers analyzed more than 5 million emergency department visits and hospitalizations related to alcohol or cannabis use across the United States. The study included more than 1.3 million people ages 16 to 64 who had at least one substance-related emergency care encounter between January 2016 and December 2023.
Among adolescents ages 16 to 18 who had a substance-related emergency visit or hospitalization, 84% had at least one encounter involving cannabis. That was the highest percentage of any age group. By comparison, cannabis was involved in 19% of substance-related encounters among adults ages 55 to 64.
Young adults ages 19 to 24 experienced the largest increase in the proportion of substance-related encounters involving cannabis during the eight-year study period, rising about 1.8 percentage points per year. The proportion among teens increased by about 0.8 percentage points annually, while rates among older age groups changed very little.
“Understanding age differences in high-risk use is critical for being able to offer effective and meaningful care for people at different life stages,” Xu said.
Xu said the increased potency of cannabis products in recent years can make it easier for people to consume much more THC, the psychoactive ingredient in cannabis.
A recent study suggested the risk of cannabis use disorder increases with consumption above roughly 40 milligrams of THC per week among adults and 30 milligrams per week among adolescents.
Xu said high-potency cannabis products pose particular risks for adolescents and young adults because their brains are still developing.
Despite an overall decline in alcohol use in the United States during the study period, alcohol-related emergency visits and hospitalizations remained common and generally increased with age.
The study also found a sharp increase in alcohol as the primary reason for hospitalization among adults ages 25 to 34. That figure rose 3.6 percentage points per year, the largest annual increase for any trend examined in the study.
“There are many lingering questions to answer, especially about understanding why substance use-related harm patterns vary so greatly across the lifespan,” said study first author Jacob Steinle. “We plan to continue our research, building upon these foundations so that clinicians can better inform each individual patient and the public at large around the risks of substance use.”
