Drugs and driving prior to cannabis legalization: A 5-year review from DECP (DRE) cases in the province of Quebec, Canada.

Objectives: To examine alleged drug-impaired driving in the province of Quebec (Canada), including drug use profile amongst suspected impaired drivers, prior to recreational cannabis legalization and major modifications to the legislation regarding driving under the influence of drugs (DUID).

Methods: The Laboratoire de sciences judiciaires et de médecine légale (LSJML) performs toxicological analyses on all biological samples collected during a Drug Evaluation and Classification Program (DECP) evaluation by a Drug Recognition Expert (DRE). A targeted analysis of 137 drugs and metabolites by liquid chromatography - tandem mass spectrometry (LC-MS/MS) is systematically carried out, enhanced by gas chromatography - mass spectrometry (GC-MS) general unknown screening if deemed necessary. Data from all DECP cases analyzed from January 2014 to December 2018 was compiled and summarized.

Results: In the 5-year period studied, a total of 2 982 DECP cases underwent toxicological analysis. Age of the intercepted drivers varied between 14-82 years old (average 33 years old), with 79 % men and 21 % women. At least one substance with impairing potential was detected in 98 % of cases. In 89 % of cases (n = 2 640), at least one substance detected matched a category of drug suspected of causing impairment. At the other end of the spectrum, there were 270 cases (9%) where the findings did not match any of the categorie(s) suspected by the DRE, 66 negative cases (2%) and 6 incomplete evaluations. Substances most commonly detected belonged to the central nervous system (CNS) stimulants (72 %), CNS depressants (61 %) and cannabis (48 %) categories. Most prevalent substances were methamphetamine (54%), cannabis (11-nor-9-carboxy-tetrahydrocannabinol or THC-COOH, 48 %), cocaine (29 %) and gamma-hydroxybutyrate (GHB, 24 %). Polydrug consumption was common, with two or more substances with impairing potential detected in 79 % of cases. There were 113 occurrences of new psychoactive substances (NPS), the most prevalent being rolicyclidine (PCPy, 47 %), methylenedioxypyrovalerone (MDPV, 17 %), methylbenzylpiperazine (MBZP, 13 %) and flubromazolam (10 %). Drug prevalence patterns varied geographically, as well as with age and gender. Indeed, methamphetamine and GHB were more popular amongst women, whereas cannabis and cocaine were more prevalent amongst men. Cannabis and CNS stimulants were more common amongst younger drivers (14-34 years old); CNS depressants, dissociative anesthetics and non-psychoactive drugs prevalence increased with age.

Conclusions: An up-to-date database of DUID cases is a powerful tool in identifying trends and threats, focusing resources and orienting research and development activities. Such a database, combined with the data presented in the current study, will be key in evaluating the impact of new regulations, i.e., recreational cannabis legalization and modifications to the DUID legislation.