Synthetic cannabinoids showed higher toxicity than THC with more seizures, deaths, and psychiatric emergencies | Research

The takeaway

A systematic review of 64 studies found synthetic cannabinoids in K2/Spice products produced more severe toxicity than THC, including 14 studies reporting deaths, with tachycardia and seizures as the most common symptoms.

Emergency medicine physicians, toxicologists, drug policy researchers

14 studies reported deaths from synthetic cannabinoids, primarily AB-CHMINACA and MDMB-CHMICA

What the researchers found

Across 64 studies (10 original papers and 54 case studies), synthetic cannabinoid use was associated with severe toxicity including death (14 studies), with AB-CHMINACA and MDMB-CHMICA most commonly involved in fatalities. Tachycardia and seizures were the most common toxicity symptoms. Third-generation synthetic cannabinoids produced higher rates of neuropsychiatric symptoms compared to earlier generations. SCs showed higher potential than THC for triggering convulsions, consciousness decline, and hemodynamic instability.

Why it matters

Synthetic cannabinoids are often used by people seeking to avoid drug tests or who cannot access regulated cannabis. Understanding their dramatically higher toxicity profile is essential for harm reduction messaging.

The numbers in context

64 studies included; 14 reported deaths; AB-CHMINACA and MDMB-CHMICA most lethal; tachycardia and seizures most common symptoms; third-generation SCs had highest neuropsychiatric symptom prevalence

How the study worked

Systematic review searching PubMed, Google Scholar, CompTox Chemicals, and Web of Science up to May 2022. Included studies analyzing synthetic cannabinoid toxicity and dependence in humans.

What this study cannot tell us

Heavy reliance on case reports and case studies (54/64). Publication bias toward severe outcomes. Difficulty identifying specific SC compounds in many cases. Polysubstance use common in reported cases.

How to read the evidence

Comprehensive systematic review across multiple databases, though reliance on case reports limits ability to estimate population-level risk.

When this study was published

Published 2023

The bigger picture

As synthetic cannabinoids evolve through generations to evade legal restrictions, they become increasingly potent and unpredictable. The irony is that cannabis prohibition drives some users toward far more dangerous synthetic alternatives.

Questions still open

Does cannabis legalization reduce synthetic cannabinoid use and associated harms? Are emergency departments equipped to recognize and treat SC-specific toxicity patterns?

Common questions

Are synthetic cannabinoids more dangerous than marijuana?

Yes. This review of 64 studies found synthetic cannabinoids produce more severe toxicity than THC, including seizures, heart problems, consciousness loss, and death. Newer generations of synthetics show even more neuropsychiatric effects.

What are the most dangerous synthetic cannabinoids?

AB-CHMINACA and MDMB-CHMICA were most commonly linked to deaths. Third-generation synthetic cannabinoids produced the highest rates of neuropsychiatric symptoms.

Read the original research

Toxicity of Synthetic Cannabinoids in K2/Spice: A Systematic Review.

Brain sciences, 13(7)

View on PubMed ↗Publisher’s paper ↗

Citation

de Oliveira, Mariana Campello; Vides, Mariana Capelo; Lassi, Dângela Layne Silva; Torales, Julio; Ventriglio, Antonio; Bombana, Henrique Silva; Leyton, Vilma; Périco, Cintia de Azevedo-Marques; Negrão, André Brooking; Malbergier, André; Castaldelli-Maia, João Maurício. (2023). Toxicity of Synthetic Cannabinoids in K2/Spice: A Systematic Review.. Brain sciences, 13(7). https://doi.org/10.3390/brainsci13070990