Emergency department presentations related to acute toxicity following recreational use of cannabis products in Switzerland, Yasmin Schmid et al., 2019

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

Yasmin Schmid, Irene Scholz, Laura Mueller, Aristomenis K. Exadaktylos,
Alessandro Ceschi, Matthias E. Liechti, Evangelia Liakoni

Drug and Alcohol Dependence, 2019.




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.

Keywords : Cannabis, THC, Emergency department, Recreational use, Acute toxicity


1. Introduction

Cannabis is the most commonly used psychoactive substance and seized drug. Prevalence of use is about five times that of other substances, and represents more than three quarters of the drugs seized in Europe (EMCDDA, 2016). Around 1 % of European adults are estimated to be daily or near-daily cannabis users and use is most frequent in young male adults aged 15–24 years (EMCDDA, 2016). Cannabis is usually smoked, commonly mixed with tobacco. Δ9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, acts as partial agonist at the cannabinoid receptors CB1, primarily located in central and peripheral neurons, and CB2, predominantly located in immune cells (Pertwee, 2008). Effects of CB1 receptor activation include decreased locomotor activity, cognitive impairment, analgesia, hypothermia, and appetite stimulation (Huestis et al., 2001, 2007). The intensity of THC effects depends on the blood THC-concentration (Crippa et al., 2012; Heishman et al., 1990; Johnson and Domino, 1971). Recreational use of cannabis is generally regarded as having low acute toxicity (Volkow et al., 2014). However, in recent years, a large increase in the potency of cannabis (i.e. level of THC) has been observed in European countries, with an increase in the number of first-time treatment entrants for cannabis-related problems (EMCDDA, 2016), which may be related to changes in the prevalence of cannabis use and/or the availability of stronger products that possibly increase the risks of use.

Collection of data related to substance use is usually based on indicators such as drug seizures at custom and borders, drug-related deaths, and surveys. However, emergency data can provide a unique insight into acute health harms and thus contribute to the prevention of medical emergencies and to the improvement of the management of acute drug toxicity (Wood et al., 2014; Heyerdahl et al., 2014). An attempt to investigate this aspect was further undertaken by the European Drug Emergencies Network (Euro-DEN plus), a European project which collects data on Emergency Department (ED) presentations with acute toxicity related to the use of recreational drugs and novel psychoactive substances (Wood et al., 2014). Of the 31 centres in 21 countries currently participating in the project, three are located in Switzerland.

The aim of this study was to describe presentations related to acute toxicity after recreational use of cannabis products at three large EDs in Switzerland, as collected within the Euro-DEN plus project. By differentiating between intoxications with cannabis alone and in combination with other substances, we aimed to investigate the differences of the effects of cannabis alone and when other substances are involved.