Synthetic cannabinoid receptor agonists (SCRAs) are suggested to have increased potential to induce psychosis compared to natural cannabis (NC). In this review we synthesise current knowledge about the association of SCRA use with psychotic symptoms. Following a literature search we identified 2 toxicology reports, 4 case-control studies, 3 cross-sectional studies and 15 case reports. In each of the case reports, we identified the presence or absence of symptoms based on the items of the Postitive and Negative Syndrome Scele (PANSS). The toxicology reports highlighted the main presenting features as being toxic psychosis and delirium (40%), agitation (10%) and hallucinations (4-7%). The median age was 25 years, and around 80% cases were male. Cross-sectional studies reported that SCRA use was present in approximately 10-13% patients presenting to acute psychiatric services, and was often the cause of their presentation, and that psychotic symptoms were present in 15% patients attending emergency departments following 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 NC users. The case reports supported the association of SCRA use with a wide range of positive and negative psychotic symptoms as well as with self-harm, agitation and aggressive behaviour. SCRA use is relatively prevalent in patients with psychosis and may lead to psychotic symptoms in individuals with no past psychiatric history. Further work is required to understand the long term risks of SCRA use and optimal management strategies.
Keywords: Cannabis; NPS; Psychosis; SCRA; Schizophrenia; Synthetic.
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