Wastewater-based epidemiology combined with local prescription analysis as a tool for temporalmonitoring of drugs trends - A UK perspective.

This paper reports the application of wastewater-based epidemiology (WBE) for the monitoring of one city in the UK in years 2014-2018 as a means of 1) exploring relative temporal changes of illicit drug usage trends across 5 sampling weeks in 5 years, (2) assessing policy impact in reducing drug consumption, focussing particularly on mephedrone, which was classified as a class B drug in the UK in 2010, and the effects of subsequent regulation such as the novel psychoactive substances (NPS) bill of 2016, (3) investigating temporal changes in consumption of prescription pharmaceuticals vs illicit drug usage, and (4) comparing consumption of prescription drugs with WBE to enable more accurate verification of prescription drugs with abuse potential. Mephedrone was quantified only for the first two years of the study, 2014-2015, and remained undetected for the next three years of the study. This shows that given enough time changes in drug policy can have an effect on drug consumption. However, after the introduction of the 2016 NPS bill, between the third and fourth study years, there was an observable increase in the consumption of "classic" drugs of abuse such as cocaine, MDMA and ketamine suggesting a shift away from novel psychoactives. The unique prescription dataset allowed for a more accurate calculation of heroin consumption using morphine by examining other sources morphine. Additionally, for compounds with controlled prescription like methadone, trends in consumption estimated by wastewater and trends in prescription correlated. Wastewater-based epidemiology is a powerful tool for examining whole populations and determining the efficacy and direction of government actions on health, as it can, alongside prescription and wider monitoring data, provide a clear insight into what is being consumed by a population and what action is needed to meet required goals.