Comprehensive guide to synthetic cannabinoids: from chemistry to toxicity | Research

The takeaway

Synthetic cannabinoids represent the largest class of new psychoactive substances with 190 substances reported to the EU by 2018, acting as more potent full agonists at cannabinoid receptors compared to THC's partial agonism, making them significantly more dangerous.

Emergency physicians, toxicologists, harm reduction workers, and drug policy researchers.

190 synthetic cannabinoids reported to the EU by 2018

What the researchers found

Synthetic cannabinoids are the largest NPS class with 190 substances reported to the EU Early Warning System (2008-2018) and ~280 reported worldwide. Unlike THC (partial agonist), synthetic cannabinoids are full agonists at cannabinoid receptors, making them much more potent. Product composition varies in both substance type and amount. Some may have long half-lives, prolonging psychoactive effects. They have been associated with deaths and acute intoxications across Europe.

Why it matters

Synthetic cannabinoids are widely available, constantly evolving to evade regulation, and significantly more dangerous than natural cannabis. Understanding their properties is essential for harm reduction and clinical response.

The numbers in context

190 substances notified to EU Early Warning System (2008-2018). ~280 reported worldwide to UNODC. Labeled "not for human consumption" to circumvent legislation. Sold as "Spice," "K2," and similar brands.

How the study worked

Comprehensive review covering development history, abuse patterns, legal status, chemical classification, and pharmacological and toxicological properties of synthetic cannabinoids.

What this study cannot tell us

Review cannot cover all emerging compounds. Toxicological data for many substances are incomplete. Legal status information rapidly becomes outdated.

How to read the evidence

Comprehensive literature review covering multiple aspects of synthetic cannabinoids, synthesizing available pharmacological and toxicological data.

When this study was published

2020 review.

The bigger picture

The rapid emergence of new synthetic cannabinoid structures outpaces regulatory responses, creating a constantly shifting landscape of uncharacterized substances with unpredictable potency and effects.

Questions still open

Can regulatory approaches keep pace with new compound emergence? Would cannabis legalization reduce synthetic cannabinoid use?

Common questions

Why are synthetic cannabinoids more dangerous than cannabis?

Unlike THC which is a partial agonist, synthetic cannabinoids are full agonists at cannabinoid receptors, making them much more potent. They also vary in composition and may have longer half-lives.

How many synthetic cannabinoids exist?

By 2018, 190 substances had been reported to the EU Early Warning System and approximately 280 worldwide, with new compounds constantly emerging to evade regulation.

Read the original research

The synthetic cannabinoids phenomenon: from structure to toxicological properties. A review.

Critical reviews in toxicology, 50(5), 359-382

View on PubMed ↗Publisher’s paper ↗

Citation

Alves, Vera L; Gonçalves, João L; Aguiar, Joselin; Teixeira, Helena M; Câmara, José S. (2020). The synthetic cannabinoids phenomenon: from structure to toxicological properties. A review.. Critical reviews in toxicology, 50(5), 359-382. https://doi.org/10.1080/10408444.2020.1762539