Michigan EDs See Jump in Cannabis-Related Neuropsychiatric Toxicity

Neuropsychiatric toxicity (NPS) was common among patients presenting with cannabis toxicity to Michigan emergency departments (EDs), and they were more likely to also have used other substances, a researcher reported.

In the community-based analysis, among more than 1,000 patients presenting with cannabis toxicity over 2 years, 39.8% also were diagnosed with NPS, most often severe anxiety (36.1%) and altered mental status (22.3%), according to Erin Leach, a fourth-year medical student at Michigan State University College of Human Medicine in Grand Rapids.

The NPS patients were more likely than the other cannabis toxicity patients to have used other substances (19.3% vs 8.6%, respectively), she reported in a presentation at the American College of Emergency Physicians (ACEP) annual meeting.

Among the patients who experienced other cannabis toxicity, intoxication (51%), and nausea/vomiting or abdominal pain (46.4%) were the most reported symptoms, and many of these patients "had mild neuropsychiatric symptoms consistent with intoxication such as blurry vision, giddiness, or disorientation," according to the authors.

Leach told MedPage Today via email that "Acute cannabis intoxication was defined as euphoria, perception alterations such as time and spatial distortion, mild motor impairment, and intensification of ordinary sensory experiences."

The frequency of all these cannabis visits surged early during the COVID-19 pandemic, according to Leach and colleagues. The frequency of all cannabis toxicity patients presenting increased sharply in May 2020 over earlier last year, with the rate for those who had inhaled cannabis doubling in May over April. That frequency was higher for both inhalers and patients who ingested cannabis at the end of the study period (October 2020) than the start, with the rate for ingesting patients steadily increasing over the 24 months studied.

In 2018, Michigan became the 10th state to legalize the use of recreational marijuana for adults. "We've got to keep educating patients on the risks of cannabis use" even in the ED, Leach told MedPage Today. "It's such a widespread thing now in our society. We need to let patients know...The best we can do is give them the knowledge to protect themselves."

Many people do not believe that cannabis can lead to medical problems, while some do not understand that ingesting cannabis (especially as an edible) takes much longer to engender the effects than inhaling (vaping, smoking) it, she noted.

The researchers conducted a retrospective cohort analysis of 1,135 consecutive patients (overall mean age 27.6) diagnosed with cannabis toxicity from November 2018 to October 2020 at seven EDs across 13 Michigan counties.

Patients with NPS were more likely to be younger (25.3 vs 29.2), female, and white (P<0.001) versus patients with cannabis toxicity. They also consumed more edible cannabis than inhaled; had significant medical and psychiatric comorbidities; had a longer ED length of stay (mean 4.8 hours); and were more likely to be admitted to the hospital or psychiatric facility (23% vs 6%).

Leach's group reported that polysubstance use was detected in 15.7% of all patients, most often ethanol and opiates.

Among patients with NPS, 14.5% had histories of psychiatric comorbidities versus 9.2% of patients with other cannabis toxicity.

Study limitations included the restrospective design, which limited causality; the potential for reporting bias; and localization to western Michigan. In addition, some patients did not specify if they had inhaled or ingested cannabis, according to the authors.

In their abstract, the researchers concluded that "These troublesome findings highlight the risks associated with the use of cannabis for recreational or therapeutic purposes."

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