Cannabis Use Prevalent In Substance-Related Adolescent Emergency Care: Insights From Kevin Xu, MD

Among adolescents with a substance-related emergency department visit, 84% had a cannabis-involved encounter, a recent study found.¹ Kevin Xu, MD, lead investigator, said this finding supported prioritizing cannabis screening when assessing substance use.² Xu cautioned that a cannabis diagnosis indicated documentation rather than causation, that cannabis seldom was the primary reason for hospitalization, and that approximately half of individuals with a cannabis-related encounter had exposure to another substance, such as alcohol or stimulants. Cannabis-related acute care presentations with diagnostic codes for vomiting, a surrogate for cannabis hyperemesis, and psychosis increased over the study period, with increases concentrated among adolescents and young adults, while alcohol as the primary reason for hospitalization rose sharply among adults ages 25 to 34. Xu stated that alcohol-related harm should not be presumed to have receded among younger adults and that these encounters represented a critical point for intervention for substance use disorders and co-occurring psychiatric disorders.

Psychiatric Times: Among adolescents with a substance-related emergency visit, 84% had a cannabis-involved encounter. What does this indicate about how clinicians should be assessing for drug use?

Kevin Xu, MD: This finding, taken in conjunction with other public health research illustrating rising cannabis use in the adolescent population, suggests that cannabis screening should be prioritized when assessing substance use. Our data includes both emergency department (ED) visits and inpatient admissions. ED claims do not designate a “primary diagnosis,” whereas inpatient claims do. Thus, in the ED, a cannabis diagnosis may be recorded even when cannabis was not the main reason for the visit. The presence of a cannabis diagnosis therefore indicates that it was documented, not that it caused the encounter.

PT: When cannabis was the primary reason for admission, the adolescent trend declined. How do you reconcile that with the rise in overall cannabis involvement?

Xu: To consider the extent to which cannabis was the “main” reason behind a substance-related admission, we conducted a number of sensitivity analyses across inpatient hospitalizations (in which we could restrict encounters that had cannabis listed as the primary diagnosis). We found that hospitalizations with cannabis as the main reason for admission were far less common than those for other substances, such as alcohol. In other words, cannabis is frequently documented in substance-related ED visits and inpatient admissions but appears to seldomly be the main reason for hospitalization.

Taken together, these findings suggest that the increase in cannabis involvement among adolescents reflects cannabis being documented more often as one of several diagnoses, rather than the primary diagnosis for admission. However, this does not mean that cannabis is “harmless” when it is not the primary diagnosis. Cannabis use frequently occurs alongside other substances, and this co-occurring use may make a presentation more serious even when cannabis is not the main reason for the visit.

Additionally, it is noteworthy to add that cannabis related acute care presentations with diagnostic codes for vomiting (a surrogate for cannabis hyperemesis) and psychosis did increase over the study’s time period, with increases concentrated amongst adolescents and young adults.

PT: Nearly half of cannabis-related encounters involved another substance. What does that tell us about how these patients present?

Xu: This is an important finding we would like to emphasize. Our data indicates that when someone has an acute care encounter involving cannabis, co-occurring substance exposure needs to be evaluated before attributing the reason for presentation solely to cannabis. Approximately half of the individuals with a cannabis related encounter had exposure to another substance, such as alcohol or stimulants. The subset of individuals who use cannabis and land in the emergency room likely represent a particularly vulnerable population, enriched not only for polysubstance use, but also comorbid psychiatric disorders (eg, mood, anxiety disorders).

PT: How does increasing product potency factor into what you’re seeing in emergency departments?

Xu: It is difficult to infer a causal relationship between increasing potency and our findings as claims data does not record potency of cannabis products. We are heartened by progress in this field, evidenced in recent work proposing weekly exposure thresholds associated with a higher risk of cannabis use disorder.³ This is a very important first step for understanding how potency is factoring into the trends that we are seeing.

PT: Alcohol as the primary reason for hospitalization rose sharply among adults ages 25 to 34. What might explain that trend?

Xu: Much attention has focused on increasing cannabis use and declining alcohol use among younger adults. Reports of declining alcohol use among younger adults have raised hope for lower rates of serious alcohol-related morbidity within this demographic. Yet these data suggest that alcohol remains a substantial contributor among young adults who present to acute care with substance-related problems.

These findings are a reminder that alcohol remains an important contributor to severe substance-related adverse events While our study was not designed to identify the causes of these trends, we need to hold off on concluding that alcohol-related harm has somehow “receded” from younger adults. One possibility is that a smaller subgroup of young adults is experiencing more severe alcohol-related harm despite declining consumption overall, although this requires further study. We also measured alcohol’s share of substance-related admissions rather than population-based rates, so the increase may partly reflect declines in admissions involving other substances.

PT: What would you highlight about this data for the practicing psychiatric clinician?

Xu: We need to take into account individualized, patient level factors when assessing for substance use in patients, as the harms related to their use are clearly not uniform across the lifespan. The growing involvement of cannabis in acute care encounters among younger patients also merits attention, particularly because it frequently occurs alongside other substance-related problems.

An important next step is to understand how and when these patients receive treatment for their substance use disorders and co-occurring psychiatric disorders as these substance-related encounters represent a critical point for intervention.

Dr Xu is an assistant professor of psychiatry at WashU Medicine.

References

1. Steinle JT, Grucza RA, Buss JL, et al. Changing patterns of alcohol and cannabis acute care admissions by age in the U.S., 2016-2023. Am J Psychiatry. Published online November 4, 2026. https://doi.org/10.1176/appi.ajp.20260023

2. Renny MH, Stecher Y, Vargas-Torres C, et al. Trends in substance use-related emergency department visits by youth, 2018-2023. Am J Emerg Med. 2025;92:1-9. https://doi.org/10.1016/j.ajem.2025.02.035

3. Thorne RL, Lawn W, Petrilli K, et al. Estimating thresholds for risk of cannabis use disorder using standard delta-9-tetrahydrocannabinol (THC) units. Addiction. 2026.