Emergency department presentations related to acute toxicity following recreational use of cannabis products in Switzerland.

Background: Concomitant use of cannabis and other psychoactive substances is common and it is often difficult to differentiate its acute effects from those of other substances. This study aimed to characterize the acute toxicity of cannabis with and without co-use of other substances.

Methods: Retrospective analysis of cases presenting at the emergency departments of three large hospitals in Switzerland due to acute toxicity related to cannabis recreational use.

Results: Among 717 attendances related to acute cannabis toxicity, 186 (26 %) were due to use of cannabis alone. The median patient age was 26 years (range 14-68), and 73 % were male. Commonly reported symptoms/signs in lone-cannabis cases included nausea/vomiting (26 %), palpitations (25 %), anxiety (23 %), and chest pain (15 %); there were no fatalities and most intoxications were of minor severity (61 %). Most patients (83 %) using cannabis alone were discharged from the emergency department, 8 % were referred to psychiatric, and two (1 %) to the intensive care; severe complications included psychosis (7 %), coma (6 %), and seizures (5 %) and one patient (<1 %) required intubation. Lone-cannabis patients presented more often with palpitations, anxiety, panic attacks, and chest pain than patients in the co-use group, whereas the latter presented more often with impaired consciousness, agitation, respiratory depression and hallucinations, and were more often admitted to psychiatric or intensive care.

Conclusion: Intoxication with cannabis alone was mostly associated with minor toxicity. Nevertheless, severe complications and cases requiring admission to intensive or psychiatric care were also reported, which indicates that intoxication with cannabis alone does not exclude considerable health risks.