Cannabis involved in most substance-related emergency visits among teens, young adults
Older adults more likely to have substance-related emergency visits involving alcohol, showing age differences in substance-related harm patterns
Sara Moser/WashU MedicineAmong people who went to the emergency department for a substance-related problem, cannabis was involved in the majority of visits by adolescents and young adults, while alcohol predominated among older adults, according to a new study by researchers at WashU Medicine.
In Brief
- Among adolescents and young adults who needed emergency care due to substance use, cannabis was involved in most cases.
- In contrast, alcohol was the primary substance involved for older adults.
- Awareness of such diverging age patterns could help doctors provide better individualized information to patients.
A large national study analyzing emergency department visits and hospitalizations related to alcohol or cannabis use across the U.S. has found diverging age patterns: Among people who presented to the hospital for a substance-related problem, cannabis was involved in the majority of visits by adolescents and young adults, while alcohol predominated among older adults.
Led by researchers at Washington University School of Medicine in St. Louis, the study appears Nov. 4 in The American Journal of Psychiatry.
Better awareness of changing patterns of harm from these substances could help clarify the risks involved in using them, according to the investigators, led by Kevin Y. Xu, MD, an assistant professor of psychiatry at WashU Medicine.
For example, the risks of cannabis use are often oversimplified and underestimated in popular media, according to Xu, especially considering the increasing potency of cannabis products readily available for purchase. The new study could help doctors provide better, more nuanced and individualized information to their patients and help them make more informed decisions around the use of alcohol and cannabis.
“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,” Xu said. “Understanding age differences in high-risk use is critical for being able to offer effective and meaningful care for people at different life stages.”
The researchers analyzed de-identified patient data from large health insurance databases, including commercial insurance and Medicaid. The analysis included more than 1.3 million individuals ages 16–64 who had at least one substance-related emergency care encounter between January 2016 and December 2023. The total number of substance-related encounters in the dataset exceeded 5 million. The data included ER visits related to opioids, stimulants and other addictive substances, along with alcohol and cannabis. The data were analyzed by age group: 16–18, 19–24, 25–34, 35–44, 45–54 and 55–64.
Shifts in substance harms by age
Among adolescents ages 16–18 who had a substance-related emergency visit or hospitalization, 84% had at least one encounter involving cannabis — the highest of any age group — compared with 19% among adults ages 55–64.
Young adults between 19 and 24 years old had the greatest increase in the proportion of encounters involving cannabis over the eight years of the study — approximately 1.8 percentage points per year. The proportion of teen encounters involving cannabis rose by about 0.8 percentage points per year over the study period, and older age groups changed very little.
Xu noted that the increased potency of cannabis products available in recent years can make it easy to consume far more THC, the psychoactive ingredient in cannabis, than in the past. One recent study suggested that cannabis use disorder becomes more likely with use above roughly 40 milligrams of THC per week in adults and 30 milligrams per week in adolescents.
According to Xu, the high potency of cannabis products poses particular risks for adolescents and young adults, who are going through critical periods of brain development. Heavy adolescent use has also been associated with increased risk of psychotic symptoms, although most people who use cannabis do not experience these problems.
While many people consume cannabis regularly without needing emergency care, the study found concerning increases in cannabis-related hospital admissions involving psychosis and severe vomiting among younger people.
Notably, when the researchers looked only at hospitalizations where cannabis was the primary reason for admission, the trend among adolescents declined — suggesting that while cannabis is increasingly present in acute care encounters, it may not be the sole driver of hospitalization, which often involved other substances or co-occurring psychiatric conditions.
The study counted any emergency visit or hospitalization where cannabis appeared anywhere in the diagnosis list, so the visit itself could have been for something else entirely, such as injury in a car accident, a psychiatric crisis or an unrelated medical problem. Nearly half of cannabis-related encounters in the study also involved at least one other substance, though the researchers did not analyze which specific conditions were listed as the main reason for admission.
Despite overall downward trends in alcohol use in the U.S. over the study’s time period, the results showed that emergency care and hospital admissions due to alcohol use remained high and tended to increase with age.
Among adolescents, 33% had an alcohol-related encounter, and this percentage rose steadily with each older age group.
Among the oldest group, ages 55–64 years, 70% had an alcohol-related encounter.
The steepest increase of any trend in the study was in alcohol as the primary reason for hospitalization among adults ages 25–34, which rose 3.6 percentage points per year.
The research team included first author Jacob T. Steinle, MD, now a clinical fellow in the department of psychiatry at Mass General Brigham. Steinle initiated and led the study as a resident in psychiatry at WashU Medicine along with co-author Suraj Shankar, MD, now a fourth-year psychiatry resident. Both were able to contribute to the study through the Psychiatry Residency Research Education Program (PRREP), which is funded, in part, by the National Institutes of Health (NIH) and co-led by Nuri B. Farber, MD, a professor of psychiatry; and Alecia Vogel, MD, PhD, an assistant professor of psychiatry.
“There are many lingering questions to answer, especially about understanding why substance use-related harm patterns vary so greatly across the lifespan,” Steinle said. “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.”
