Misrepresentation of MDMA in the United States, 1999-2023

Background and aims: The misrepresentation of illicit drugs in unregulated markets increases the risk of adverse health events. This study analyzed drug checking data to compare represented, expected, and actual content of alleged MDMA samples, estimate trends in the quality of the MDMA supply, document the presence of adulterants, compare patterns of adulteration, and validate drug checking against law enforcement data. Method: The study analyzed 4719 alleged MDMA samples submitted to the DrugsData drug checking service between 1999-2023. Measures captured characteristics and quality of the MDMA supply, including represented content, expected and actual content, sample form, and specific adulterants. Tests of association were conducted using Pearson's chi-square or Spearman's rho, and tests for trends were performed using joinpoint regression. Finding: Most samples (75 %) were expected to contain MDMA, but this varied significantly by represented content (p<0.001). About half the samples (48 %) contained MDMA-only, which also varied significantly by represented content (p<0.001). MDMA-only prevalence declined from 1999-2009 (57.4-15.2 %, p<0.05), recovered from 2009-2017 (15.2-56.0 %, p<0.05), and increased more moderately from 2017-2023 (56.0-74.1 %, p<0.05). Overall, 199 unique adulterants were detected in the MDMA supply across 25 years. We confirmed robust correlations in adulterant prevalence trends between drug checking and law enforcement seizure data. Conclusions: While users typically expected alleged MDMA samples to contain only MDMA, more than half of the submitted MDMA samples were misrepresented in some manner. Despite high levels of misrepresentation, MDMA quality has stabilized at relatively high levels in recent years