Synthetic Cannabinoids Cause More Severe Neurological Emergencies Than Natural Cannabis | Research

The takeaway

Emergency department data from 24 European countries showed synthetic cannabinoids caused significantly more drowsiness, coma, agitation, and seizures, while cannabis was linked to cardiovascular symptoms.

Emergency physicians and toxicologists; drug policy researchers comparing risks of natural and synthetic cannabinoids.

2,657 cannabis vs 503 synthetic cannabinoid lone exposures across 24 countries

What the researchers found

Synthetic cannabinoid presentations had significantly higher rates of drowsiness, coma, agitation, seizures, and bradycardia. Cannabis presentations had significantly higher rates of palpitations, chest pain, hypertension, tachycardia, anxiety, vomiting, and headache. Synthetic cannabinoid patients were more likely to be admitted to psychiatric wards.

Why it matters

Synthetic cannabinoids are often marketed as "legal" cannabis alternatives but produce a fundamentally different and more dangerous clinical picture. This large multinational dataset reveals that the two substance classes lead to distinct patterns of emergency department presentations with different organ system involvement.

The numbers in context

54,314 total drug-related presentations. 2,657 lone cannabis exposures. 503 lone synthetic cannabinoid exposures. Synthetic cannabinoids had statistically significantly higher rates of drowsiness, coma, agitation, seizures, and bradycardia (all p < 0.05). Cannabis had higher rates of palpitations, chest pain, hypertension, tachycardia, anxiety, vomiting, and headache (all p < 0.05).

How the study worked

Retrospective cohort study using the European Drug Emergencies Network Plus, a surveillance system across 36 centers in 24 European countries from 2013-2020. Compared 2,657 lone cannabis exposures with 503 lone synthetic cannabinoid exposures among 54,314 total drug-related presentations.

What this study cannot tell us

Drug identification relies on patient self-report in the emergency department, which may be inaccurate. Some synthetic cannabinoid users may not know what substance they consumed. The study cannot account for dose, potency, or specific compound within the synthetic cannabinoid class.

How to read the evidence

Moderate: large multinational dataset with standardized data collection, though limited by self-reported substance identification.

When this study was published

2024 study analyzing 2013-2020 data.

The bigger picture

Synthetic cannabinoids remain the largest group of new psychoactive substances globally. Understanding their distinct toxicity profile versus natural cannabis helps emergency physicians recognize and manage exposures appropriately and informs drug policy discussions about the relative risks of these substance classes.

Questions still open

Do specific synthetic cannabinoid compounds produce different toxicity profiles? Would the pattern of clinical features shift with changes in the synthetic cannabinoid market over time?

Common questions

Why are synthetic cannabinoids more dangerous?

Unlike THC which is a partial agonist at cannabinoid receptors, many synthetic cannabinoids are full agonists with much higher potency. This leads to more severe neurological effects including coma and seizures that are rarely seen with natural cannabis.

What cardiovascular effects does cannabis cause?

Cannabis presentations showed significantly higher rates of tachycardia (fast heart rate), hypertension, palpitations, and chest pain compared to synthetic cannabinoids, which instead caused bradycardia (slow heart rate).

Read the original research

Clinical effects of cannabis compared to synthetic cannabinoid receptor agonists (SCRAs): a retrospective cohort study of presentations with acute toxicity to European hospitals between 2013 and 2020.

Clinical toxicology (Philadelphia, Pa.), 62(6), 378-384

View on PubMed ↗Publisher’s paper ↗

Citation

Waters, Mitchell L; Dargan, Paul I; Yates, Christopher; Dines, Alison M; Eyer, Florian; Giraudon, Isabelle; Heyerdahl, Fridtjof; Hovda, Knut Erik; Liechti, Matthias E; Miró, Òscar; Vallersnes, Odd Martin; Anseeuw, Kurt; Badaras, Robertas; Bitel, Marcin; Bonnici, Jeffrey; Brvar, Miran; Caganova, Blazena; Calýskan, Feriyde; Ceschi, Alessandro; Chamoun, Karam; Daveloose, Laurence; Galicia, Miguel; Gartner, Birgit; Gorozia, Ketevan; Grenc, Damjan; Gresnigt, Femke M J; Hondebrink, Laura; Jürgens, Gesche; Konstari, Jutta; Kutubidze, Soso; Laubner, Gabija; Liakoni, Evangelia; Liguts, Viesturs; Lyphout, Cathelijne; McKenna, Roy; Mégarbane, Bruno; Moughty, Adrian; Nitescu, Gabriela Viorela; Noseda, Roberta; O'Connor, Niall; Paasma, Raido; Ortega Perez, Juan; Perminas, Marius; Persett, Per Sverre; Põld, Kristiina; Puchon, Erik; Puiguriguer, Jordi; Radenkova-Saeva, Julia; Rulisek, Jan; Samer, Caroline; Schmid, Yasmin; Scholz, Irene; Stašinskis, Roberts; Surkus, Jonas; Van den Hengel-Koot, Irma; Vigorita, Federico; Vogt, Severin; Waldman, Wojciech; Waring, William Stephen; Zacharov, Sergej; Zellner, Tobias; Wood, David M. (2024). Clinical effects of cannabis compared to synthetic cannabinoid receptor agonists (SCRAs): a retrospective cohort study of presentations with acute toxicity to European hospitals between 2013 and 2020.. Clinical toxicology (Philadelphia, Pa.), 62(6), 378-384. https://doi.org/10.1080/15563650.2024.2346125