INTRODUCTION: New psychoactive substances (NPS) present a unique challenge in clinical, public health and drug-policy contexts. Continued diversity, unknown potency and often unintentional exposure can limit the accuracy of self-reported data. This study examined the accuracy of patient-reported NPS and illicit drug exposure in Australian emergency departments (ED).

METHODS: Patient-reported drug exposure, clinical and toxicology data were extracted from the Emerging Drugs Network of Australia Clinical Registry between 1 July 2021 and 30 June 2024 for patients presenting with severe and/or unusual illicit drug toxicity in the ED. Blood samples were analysed using mass spectrometry. Agreement between reported and confirmed exposure was assessed using Cohen's kappa, sensitivity, specificity and likelihood ratios. Logistic regression analysis identified factors associated with discrepancies between reported and confirmed exposures.

RESULTS: There were 2044 presentations: 64.6% male, median age 33 years (Q1-Q3, 26-41). Complete agreement between patient-reported and confirmed drug exposures was 14.3% (n = 293). Agreement between reported and confirmed NPS exposure was poor (κ = 0.38). 1522 (74.5%) had more drugs detected than reported. Older age (OR 1.03 [CI 1.02, 1.04]) was associated with higher odds of discrepancy. Attendance from a licensed venue (OR 0.44 [CI 0.28, 0.70]) and Glasgow Coma Scale of 13-15 (OR 0.44 [CI 0.33, 0.57]) were associated with lower odds.

DISCUSSION AND CONCLUSIONS: Poor agreement between patient-reported and analytically confirmed drug exposure highlights the need for continued partnerships between EDs, clinical toxicologists, and forensic laboratories to identify substances involved in acute intoxications and support public health and harm reduction responses.