Systematic review found synthetic cannabinoids present in 10-13% of acute psychiatric patients and strongly associated with psychosis | Research

The takeaway

A systematic review of 24 studies found that synthetic cannabinoid use was present in 10-13% of acute psychiatric service patients, associated with higher positive psychotic symptoms than natural cannabis, and capable of causing psychosis in people with no psychiatric history.

Read this if you want to understand the psychosis risks of synthetic cannabinoids compared to natural cannabis.

10-13% of acute psychiatric patients had used synthetic cannabinoids

What the researchers found

Researchers synthesized evidence from 2 toxicology reports, 4 case-control studies, 3 cross-sectional studies, and 15 case reports on synthetic cannabinoid receptor agonists (SCRAs) and psychosis.

The toxicology reports identified toxic psychosis and delirium (40%), agitation (10%), and hallucinations (4-7%) as main presenting features. The median age was 25 years and approximately 80% were male.

Cross-sectional studies found SCRA use present in 10-13% of patients presenting to acute psychiatric services, often as the cause of their presentation. Psychotic symptoms were present in 15% of patients attending emergency departments after SCRA use.

Case-control studies reported that SCRA use was significantly associated with psychotic symptoms and that SCRA users had higher levels of positive psychotic symptoms than natural cannabis users.

Case reports documented a wide range of positive and negative psychotic symptoms, self-harm, agitation, and aggressive behavior. Importantly, SCRA use could trigger psychosis in individuals with no past psychiatric history.

Why it matters

This systematic review provides the most comprehensive picture to date of the SCRA-psychosis relationship, demonstrating that synthetic cannabinoids carry greater psychosis risk than natural cannabis and affect a significant proportion of acute psychiatric presentations.

The numbers in context

24 studies reviewed. SCRA use in 10-13% of acute psychiatric patients. 15% of ED SCRA patients had psychotic symptoms. 40% of toxicology cases had toxic psychosis/delirium. Median age 25, ~80% male. Higher positive symptoms than natural cannabis users.

How the study worked

Systematic literature review identifying 24 studies (2 toxicology reports, 4 case-control, 3 cross-sectional, 15 case reports). Case report symptoms coded against PANSS items. Studies covered multiple countries and clinical settings.

What this study cannot tell us

The evidence base is heavily weighted toward case reports, which have inherent selection and reporting biases. Many studies could not confirm SCRA identity through toxicological analysis. Polysubstance use was common. Long-term outcomes after SCRA-induced psychosis were rarely documented.

How to read the evidence

Systematic review synthesizing 24 studies across multiple designs provides moderate evidence, limited by reliance on case reports and cross-sectional data.

When this study was published

Published in 2018. New synthetic cannabinoid compounds continue to emerge with potentially different risk profiles.

The bigger picture

The finding that 10-13% of acute psychiatric patients have used SCRAs means this is not a rare phenomenon. SCRAs represent a distinct risk category from natural cannabis, with more severe psychotic presentations and the ability to trigger psychosis de novo. This has implications for psychiatric screening and substance-specific interventions.

Questions still open

Do SCRA-induced psychotic episodes resolve after cessation, or do they persist? What specific SCRA compounds carry the highest psychosis risk? Should psychiatric screening routinely test for synthetic cannabinoids separately from natural cannabis?

Common questions

Are synthetic cannabinoids worse for psychosis than natural cannabis?

Yes. Case-control studies in this review found that SCRA users had higher levels of positive psychotic symptoms than natural cannabis users. SCRAs were also capable of causing psychosis in people with no prior psychiatric history.

How common is synthetic cannabinoid use among psychiatric patients?

Cross-sectional studies found SCRA use in 10-13% of patients presenting to acute psychiatric services, often as the direct cause of their psychiatric presentation.

Read the original research

Spicing it up - synthetic cannabinoid receptor agonists and psychosis - a systematic review.

European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 28(12), 1289-1304

View on PubMed ↗Publisher’s paper ↗

Citation

Hobbs, Melissa; Kalk, Nicola J; Morrison, Paul D; Stone, James M. (2018). Spicing it up - synthetic cannabinoid receptor agonists and psychosis - a systematic review.. European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 28(12), 1289-1304. https://doi.org/10.1016/j.euroneuro.2018.10.004