What We Know About the Behavioral Effects and Risks of Synthetic Cannabinoids ("Spice") | Research

The takeaway

Scientific research on synthetic cannabinoids is still in early stages, but available evidence indicates these compounds carry significant abuse potential, tolerance, dependence, withdrawal, and toxicity risks that often exceed THC.

Read this if you want to understand what science says about the dangers of synthetic cannabinoids like "Spice" and "K2."

Synthetic cannabinoids were never intended for human use and research is still in early stages

What the researchers found

This review consolidated the scientific literature on "Spice" compounds, synthetic cannabinoids originally designed as research tools that became widely abused recreational drugs.

In behavioral assays comparing synthetic cannabinoids to THC, the synthetic compounds generally produced similar effects but often at greater potency or with additional toxicity. Studies documented abuse liability (animals will self-administer these compounds), rapid tolerance development, physical dependence, and withdrawal symptoms.

The review emphasized that these compounds were never intended for human consumption and that scientifically based information about their toxicity and long-term behavioral effects is extremely limited. Most safety data comes from emergency department reports and case series rather than controlled studies.

Methodological challenges include the constant appearance of new compounds, variable composition of street products, and difficulties administering these compounds in controlled research settings.

Why it matters

Synthetic cannabinoids remain a significant public health threat, particularly among populations without access to regulated cannabis and those subject to drug testing. This review highlights how little is actually known about compounds that thousands of people have consumed.

The numbers in context

The review covers multiple synthetic cannabinoid compounds but does not provide pooled statistics. It notes the "fairly recent" nature of recreational use and the nascent state of preclinical research.

How the study worked

Literature review consolidating published behavioral studies of synthetic cannabinoids in both animals and humans, comparing effects to THC. Covers abuse liability, tolerance, dependence, withdrawal, and toxicity data.

What this study cannot tell us

Much of the evidence comes from anecdotal reports and case series rather than controlled studies. The rapid turnover of compounds on the market means research is always behind the current products. Most preclinical studies focus on a small number of compounds that may not represent the full range of products available.

How to read the evidence

Literature review covering animal and human behavioral data. Moderate because it synthesizes legitimate evidence but the underlying research base is limited and rapidly evolving.

When this study was published

Published in 2017.

The bigger picture

The synthetic cannabinoid phenomenon illustrates what happens when prohibition drives users toward unregulated alternatives. The compounds are generally more potent and more dangerous than the natural product they were designed to mimic, creating a paradox where drug policy intended to reduce harm may have increased it.

Questions still open

How can research keep pace with the constantly evolving synthetic cannabinoid market? Would legal access to regulated cannabis reduce synthetic cannabinoid use? Are there long-term neurological effects from synthetic cannabinoid use that have not yet been identified?

Common questions

Are synthetic cannabinoids more dangerous than marijuana?

Available evidence suggests yes. Synthetic cannabinoids generally produce similar effects to THC but at greater potency, with additional toxicity risks. They were never designed for human consumption and their long-term effects are largely unknown.

Can you get addicted to synthetic cannabinoids?

Research shows synthetic cannabinoids carry abuse liability (animals will self-administer them), and users can develop tolerance, physical dependence, and experience withdrawal symptoms, similar to but potentially more severe than with natural cannabis.

Read the original research

Tripping with Synthetic Cannabinoids ("Spice"): Anecdotal and Experimental Observations in Animals and Man.

Current topics in behavioral neurosciences, 32, 263-281

View on PubMed ↗Publisher’s paper ↗

Citation

Järbe, Torbjörn U C; Raghav, Jimit Girish. (2017). Tripping with Synthetic Cannabinoids ("Spice"): Anecdotal and Experimental Observations in Animals and Man.. Current topics in behavioral neurosciences, 32, 263-281. https://doi.org/10.1007/7854_2016_16