30 years of New Psychoactive Substances (NPS) in Europe. A first integrated public health assessment.

Background 
Since the early 1990s, NPS started to be reported in Europe. In 1997, the EU took significant steps by adopting Joint Action on NPS (97/396/JHA), followed by additional legislation in 2006 and 2017.  In the EU, 930 NPS were identified between 2005 and end of 2022 raising considerable concern. However, to our knowledge, after 30 years, there has not been an integrated public health assessment of the impact of the phenomenon.
Methods 
This presentation analyzes information from existing public sources (e.g. EMCDDA reports, scientific publications) on prevalence of use, health consequences and availability of NPS in Europe. 
Results    
National general population surveys conducted in 19 EU countries and Norway, with harmonized instruments, found a Last 12 Month Prevalence (LYP) (weighted average) of 0.6% among 15-64 y.o. (range of 0.1% to 1.4%) and 1.1% among 15-34 y.o. (0.1% to 3.2%). (Vicente et al, 2019).  The European ESPAD project (school surveys in 35 European countries) reported a non-weighted average LYP of 2.5% in 2019, although this is possibly an overestimation.  The 2021 Global Drug Survey (32.000 participants from 20 countries) reported very high levels of substance use (licit and illicit) but LYP of specific NPS (e.g. 2CB -6.1%-, DMT -4.8%-) were substantially lower than minority traditional drugs (e.g. LSD -21% and Ketamine 15.9%-). (Winstock, 2021).
Wastewater-based epidemiology (WWE) studies avoid any self-reporting bias. A study conducted in 2016-2017 on 24 cities of 16 EU countries investigated the presence of almost 200 NPS in WW, but only 13 were found, and in very low concentrations (Salgueiro-González et al. 2019, NPS Euronet project).
Information on drug treatments for NPS abuse is collected at EU level. Although it has not been published, it is estimated that the numbers are very low.  An ongoing study on drug-related hospital emergencies (Euro-DEN project) including 31 hospitals from 21 European countries, reported that 6.2% of cases were related to NPS (2014-2017). A European overview reported that in 2016 and 2017, NPS were found in 14.6% of the Drug Induced Deaths. However, 75.1% of cases were reported in only two countries (UK and Turkey) and related to only two substances. (Lopez-Pelayo et al. 2021)
The amount of NPS seized is markedly lower compared with classical drugs: e.g. in 2019, seizures of classical cannabis were 785 times higher than synthetic cannabinoids, and those of classical stimulants 342 times higher than synthetic cathinones.
Conclusions
An integrated public health assessment of the NPS situation is essential for evidence-based policies. A first analysis of published information indicates that, in the EU, the overall public health impact of NPS is limited, although on vulnerable groups, it may be more significant. Improving available sources of information and conducting further analysis is crucial to confirm the findings of this assessment and guide policymaking