U.S. Poison Center exposure cases involving marijuana and selected comparator substances

With increasing number of U.S. states legalizing marijuana use, nearly half now allow adult use. Consequently, harms from marijuana exposures are increasing. We describe recent levels, characteristics, and trajectory of harms associated with intentional and unintentional marijuana use compared to other drugs.

We examined exposure characteristics, medical outcomes, and utilization-adjusted rates (per million people with past-year nonmedical use from National Survey on Drug Use and Health) for U.S. Poison Center cases (2013-2021) involving marijuana recreational use (RU) and unintentional exposure compared to selected licit (alcohol, zolpidem, benzodiazepines, ketamine, tramadol, hydrocodone, oxycodone) and illicit (cocaine, heroin) comparators.

Marijuana RU exposure cases (n = 22,731) exceeded comparator cases (n = 832-15,196), except for alcohol (n = 56,143), benzodiazepines (n = 33,688), and heroin (n = 34,083). Marijuana RU cases commonly involved adolescents (46%). Marijuana single-substance RU exposure cases less commonly resulted in major effects (3%) or death (0.04%) than comparator drugs (3-40%, and 0.1-2.5%, respectively), except zolpidem (deaths 0%). Marijuana utilization-adjusted RU case rates increased over time but remained lower than comparators' rates, except alcohol. Marijuana unintentional exposure cases (n = 15,301) increased 10-fold over the time-period and primarily involved children < 6 years (70%) and edibles (51%). Although observed pediatric marijuana unintentional exposure cases were non-fatal, serious outcomes were more common than for licit comparators.

We found increasing frequency of marijuana harms from RU, generally less severe outcomes for marijuana cases versus several comparator drugs, and increasing unintentional marijuana exposure cases, suggesting the need for safe storage and public education for marijuana poisoning prevention, particularly in children and adolescents.