Association of the 2016 UK Psychoactive Substance Act with hospital presentations following analytically confirmed synthetic cannabinoid receptor agonist exposure.

The United Kingdom (UK) Psychoactive Substances Act (PSA), implemented on the 26th May 2016, made the production, supply, and sale of all non-exempted psychoactive substances illegal. The aim of this study was to examine the association between the implementation of the PSA and the number of hospital presentations with severe toxicity following analytically confirmed synthetic cannabinoid receptor agonist (SCRA) exposure. As part of the Identification of Novel Psychoactive Substances (IONA) Study, biological samples were collected from 627 patients (79.8% male) presenting to participating hospitals in the UK with severe acute toxicity following suspected use of novel psychoactive substances (NPS) between July 2015 and December 2019. Samples were analysed using liquid-chromatography tandem mass-spectrometry (LC-MS/MS). Time-series analysis was conducted on the monthly number of patients with and without analytically confirmed SCRA exposure using Poisson segmented regression.

SCRAs were detected in 35.7% (n=224) of patients. Before the implementation of the PSA, there was evidence of an upward trend in monthly SCRA exposure cases (IRR: 1.12, 95% CI: 1.00 – 1.26, p=0.046). After its implementation, the level of the series (i.e. y-intercept) fell by 49% (IRR: 0.45, 95% CI: 0.25 – 0.81, p=0.008) and the trend of the series (i.e. regression slope) was 13% lower than before the PSA was introduced (IRR: 0.87, 95% CI: 0.79 – 0.96, p=0.005). For non-SCRA exposure cases, there was no significant upward or downward trend prior to the implementation of the PSA or any significant change in the level or trend in the series after its implementation (p > 0.05). Implementation of the 2016 PSA was associated with a reduction in the number of patients presenting to UK hospitals with severe acute toxicity following analytically confirmed SCRA exposure.