Which Legal Substance Is Most Likely To Help Land You In The Hospital? Depends On Your Age

THURSDAY, Nov. 5, 2026 (HealthDay News) — Which legal substance is most likely to help land you in the emergency room?

It depends on your age, a new study says.

Weed is the substance most likely to be tied to a hospital visit among teens and young adults, while booze was linked to visits among middle-aged folks, researchers reported Wednesday in The American Journal of Psychiatry.

The risks of weed are often oversimplified and underestimated in popular media, especially given the increasing potency of legal cannabis potency, researchers said.

“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 senior researcher Dr. Kevin Xu, an assistant professor of psychiatry at Washington University School of Medicine in St. Louis.

“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 in a news release.

For the new study, researchers analyzed medical records for more than 1.3 million Americans between 16 and 64 years of age who’d had at least one substance-related ER visit between 2016 and 2023. The records were drawn from large commercial insurance and Medicaid databases. 

Results showed that weed was the substance that helped send 84% of 16- to 18-year-olds and 68% of 19- to 24-year-olds to the ER at least once, compared with 19% of 55- to 64-year-olds.

Conversely, alcohol was at least partly responsible for 70% of substance-related ER visits among middle-aged people, compared to 33% of teens and 38% of young adults.

ER visits involving weed increased most among young adults 19 and 24, rising nearly 2 percentage points per year during the eight years of the study, researchers said.

Researchers noted concerning increases in weed-related hospital admissions involving psychosis and severe vomiting among younger people.

However, the overall trend among teenagers declined when the team looked only at hospitalizations where weed was the primary reason for admission.

Researchers said this suggests that weed might not be the sole driver of hospitalization but instead could be interacting with other substances or existing mental health problems.

The study counted any ER visit or hospitalization where weed was cited anywhere in a person’s diagnosis, so the visit itself could have been for something else entirely — an injury, a car accident, a mental health crisis or an unrelated medical problem, researchers noted.

Nearly half of the weed-related encounters in the study involved at least one other substance, the team said.

“There are many lingering questions to answer, especially about understanding why substance use-related harm patterns vary so greatly across the lifespan,” said lead researcher Dr. Jacob Steinle, a clinical fellow of psychiatry at Mass General Brigham in Boston.

“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,” he said.

More information

The U.S. Centers for Disease Control and Prevention has more on the health effects of weed.

SOURCES: Washington University School of Medicine in St. Louis, news release, Nov. 4, 2026; The American Journal of Psychiatry, Nov. 4, 2026