Festivals following the easing of COVID-19 restrictions: Prevalence of new psychoactive substances and illicit drugs.

During New Year celebrations and a summer festival in a large Spanish city, wastewater samples revealed high consumption of both new psychoactive substances (NPS) and traditional illicit drugs. Eleven NPS—including synthetic cathinones, benzodiazepines, plant-based NPS, and dissociatives—plus seven illicit drugs were detected across both events. Consumption peaked at each event, and drug use patterns shifted markedly over the six months between them. Statistically significant differences were observed for 3-MMC, eutylone, cocaine, MDMA, heroin, and pseudoephedrine when comparing the two events or a normal week. Wastewater-based epidemiology offers a cost-effective, timely, and ethically straightforward way to monitor drug use and complement public health surveillance.

Study at a glance

Abstract

The market for illicit drugs and new psychoactive substances (NPS) has grown significantly and people attending festivals have been identified as being at high risk (high extent and frequency of substance use). Traditional public health surveillance data sources have limitations (high costs, long implementation times, and ethical issues) and wastewater-based epidemiology (WBE) can cost-effectively support surveillance efforts. Influent wastewater samples were analyzed for NPS and illicit drug consumption collected during New Year period (from 29-Dec-2021 to 4-Jan-2022) and a summer Festival (from 29-June-2022 to 12-July-2022) in a large city in Spain. Samples were analyzed for phenethylamines, cathinones, opioids, benzodiazepines, plant-based NPS, dissociatives, and the illicit drugs methamphetamine, MDA, MDMA, ketamine, heroin, cocaine, and pseudoephedrine by liquid chromatography mass spectrometry. High consumption rates of specific NPS and established illicit drugs were identified at the peak of each event. Furthermore, a dynamic change in NPS use (presence and absence of substances) was detected over a period of six months. Eleven NPS, including synthetic cathinones, benzodiazepines, plant-based NPS and dissociatives, and seven illicit drugs were found across both the New Year and summer Festival. Statistically significant differences (p < 0.05) were seen for 3-MMC (New Year vs summer Festival), eutylone (New Year vs summer Festival), cocaine (summer Festival vs normal week and summer Festival vs New Year), MDMA (New Year vs normal week and summer Festival vs normal week), heroin (summer Festival vs New Year) and pseudoephedrine (summer Festival vs New Year). This WBE study assessed the prevalence of NPS and illicit drugs at festivals following the reduction of the COVID-19 pandemic restrictions highlighting the high use of specific substances at the peak of each event. This approach identified in a cost-effective and timely manner without any ethical issues the most used drugs and changes in use patterns and, thus, can complement public health information.