Self-Reported Adverse Effects Associated With New Psychoactive Substance Use in a Sample of Adults From 20 US Cities

As new psychoactive substances (NPS) continue to emerge both in the US and globally, research is needed to determine the extent of adverse effects associated with NPS use beyond poisonings or mortality to inform prevention and harm reduction efforts in this population.

Data were from the National Drug Early Warning System Rapid Street Reporting study, which uses a venue-intercept design to survey adults (≥ 18 years) in US cities over weekend periods. Between January 2022 and November 2023, 6039 individuals were surveyed in 20 cities regarding their use of a range of NPS and other common drugs. Those reporting past 12-month use of a drug were asked if they experienced a harmful or very unpleasant effect after use.

Overall, among those reporting any past 12-month NPS use (n = 259), over a quarter (27.03%) reported experiencing an adverse effect related to the use of at least one NPS in the past 12 months. Among those reporting NPS use, those who also reported past 12-month opioid use had over two times the prevalence of reporting an adverse effect related to NPS use (adjusted prevalence ratio 2.66, 95% confidence interval 1.41, 5.01). Symptom profiles were broadly similar between NPS and common drug classes.

Adverse effects from NPS appear to be common among those self-reporting NPS use, particularly among those reporting polysubstance use. More data are needed to determine event-specific adverse outcomes involving the use of NPS and other drugs.