- Across 2010-2016, 40.5% of RPU reported use of ‘any’ NPS in the preceding six months; this fluctuated considerably over the years.
- Synthetic cathinones were the most prevalent NPS used by RPU in 2010 (18.5%), but had declined significantly by 2016 (3.3%;p<0.001).
- In 2010 both phenethylamine and tryptamine NPS had been used by 8% of RPU in the six months preceding interview; this increased to 14.2% (p<0.001) and 15.6% (p<0.001) respectively in 2016, making them the two most commonly used groups of NPS.
- Rates of synthetic cannabinoid use fluctuated over the years, with 4.2% of RPU reporting recent use in 2016.
- Recent use of plant-based NPS increased from 2.0% in 2010 to 5.2% in 2016 (p=0.003).
- Recent use of benzylpiperazine declined from 4.9% in 2010 to 0% in 2016 (p<0.001).
- Recent use of methoxetamine and aminoindanes (i.e. MDAI, 5-IAI) remained stable and uncommon across all years.
- NPS markets remain highly dynamic, with the popularity of NPS classes changing overtime.