Development of an evidence-based classification framework for psychoactive substances in the illicit drug market

Context: Better understanding how drug market evolves in the type of substances available and threats posed is crucial to adequately respond to substance related harms. To facilitate monitoring of substances in the illicit drug market and global collaboration, Health Canada's Drug Analysis Service (HC-DAS) partnered with the United States’ White House Office of National Drug Control Policy (ONDCP), U.S. Customs and Border Protection, the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), and the United Nations Office on Drugs and Crimes (UNODC) to develop a harmonised and evidence-based classification system for psychoactive substances. This classification aims to support the efforts of public health professionals, forensic chemists and data specialists to better integrate timely drug data, particularly laboratory data, into their surveillance systems, for routine monitoring and early warning purposes.

Method: The databases of substances from HC-DAS, ONDCP, EMCDDA and UNODC were compared. HC-DAS resolved differences in classifications through literature review and by consulting with experts in pharmacology and chemistry.  New classes were introduced to capture previously unclassified psychoactive substances with public health relevance, along with corresponding definitions.

Outcome: The proposed classification framework comprises 10 pharmacological classes, including five from initial frameworks (stimulants, hallucinogens, sedative/ hypnotics, opioids and dissociative). While classes for ‘cannabimimmetics’ and ‘synthetic cannabinoid receptor agonist’ are used, HC-DAS opted for a broader 'cannabinoids' class, which also captures semi-synthetic cannabinoids. Under HC-DAS's proposed framework, classes for steroids, selective androgen/estrogen receptor modulators (SARM/SERM) and drugs for erectile dysfunction were combined under the overarching 'physical performance enhancer' class.  Three additional classes (antidepressants, antipsychotics and cognitive enhancers) were created to capture substances of potential public health relevance. Finally, some non-psychoactive substances such as cutting agents, precursor chemicals and intermediate reagents were also categorized. Over 1000 substances were classified within the proposed framework and this list is routinely updated with new psychoactive substances.  Substance classifications are routinely reviewed in accordance with the latest evidence and scientific consensus to ensure ongoing relevance for partners.

Conclusion: This is the first classification framework for psychoactive substances that was developed within a multi-organizational partnership. To our knowledge, the unified list is the most comprehensive list of classified psychoactive substances to be accessible to partners upon request and will be instrumental in facilitating global cooperation to address the dynamic challenges posed by the evolving drug market.