Trends in hospital presentations following analytically confirmed synthetic cannabinoid receptor agonist exposure before and after implementation of the 2016 UK Psychoactive Substances Act

Abstract

Background and aims: The United Kingdom (UK) Psychoactive Substances Act (PSA), implemented on the 26^th May 2016, made the production, supply and sale of all non-exempted psychoactive substances illegal. The aim of this study was to measure trends in hospital presentations for severe toxicity following analytically confirmed synthetic cannabinoid receptor agonist (SCRA) exposure before and after implementation of the PSA.

Design: Observational study.

Setting: Thirty-four hospitals across the UK participating in the Identification of Novel Psychoactive Substances (IONA) study.

Participants: A total of 627 (79.9% male) consenting individuals who presented to participating hospitals between July 2015 and December 2019 with severe acute toxicity and suspected novel psychoactive substances exposure.

Measurements: Toxicological analyses of patient samples were conducted using liquid-chromatography tandem mass-spectrometry. Time-series analysis was conducted on the monthly number of patients with and without analytically confirmed SCRA exposure using Poisson segmented regression.

Findings: SCRAs were detected in 35.7% (n = 224) of patients. After adjusting for seasonality and the number of active sites, models showed no clear evidence of an upward or downward trend in the number of SCRA exposure cases in the period before (incidence rate ratio [IRR], 1.12; 95% CI, 0.99-1.26; P = 0.068) or after (IRR, 0.97; 95% CI, 0.94-1.01; P = 0.202) the implementation of the PSA. There was also no clear evidence of an upward or downward trend in non-SCRA exposure cases before (IRR, 1.12; 95% CI, 0.98-1.27; P = 0.105) or after (IRR, 1.01; 95% CI, 0.98-1.04; P = 0.478) implementation of the PSA.

Conclusions: There is no clear evidence of an upward or downward trend in the number of patients presenting to UK hospitals with severe acute toxicity following analytically confirmed synthetic cannabinoid receptor agonist exposure since the implementation of the Psychoactive Substances Act.

Keywords: NPS; PSA; Psychoactive Substances Act; SCRA; synthetic cannabinoid receptor agonists; time series analysis; toxicity.

FIGURE 1

Prevalence of individual SCRA compounds detected among SCRA exposure cases within each year between July 2015 and December 2019. Note: Only compounds detected in ≥9 cases are displayed. SCRA, synthetic cannabinoid receptor agonist

FIGURE 2

Prevalence of drugs detected among SCRA and non‐SCRA exposure cases. Note: SCRA exposure cases are those where at least one SCRA was detected, non‐SCRA exposure cases are those where no SCRAs, but at least one drug (previously controlled under the MDA before July 2015) was detected. SCRA, synthetic cannabinoid receptor agonist; THC, delta‐9‐tetrahydrocannabinol; MDA, Misuse of Drugs Act; MDMA, 3,4‐methyl​enedioxy​methamphetamine

FIGURE 3

(a) Observed and predicted number of SCRA exposes cases within each month between July 2015 to December 2019 based on segmented Poisson regression estimating trends before and after implementation of the PSA (see Table 1). (b) Observed and predicted number of non‐SCRA exposes cases within each month between July 2015 to December 2019 based on segmented Poisson regression estimating trends before and after implementation of the PSA (see Table 1). Note: Predicted number of cases refer to fitted values (and the 95% CI bands) of the final segmented Poison regression models reported in Table 1, whereas the observed cases are the true number of hospital presentations across the study period. SCRA, synthetic cannabinoid receptor agonist; PSA, Psychoactive Substances Act