Substance use and type of Road Traffic Injury in Mexico City.

Limited data are available in Mexico on the prevalence of alcohol and drug use and the possible differences in their effects on types of road traffic injury (RTI), such as those involving pedestrians, drivers or passengers of motorcycles or other motor vehicles, and the association between substance use and driving behaviors, for preventive purposes. The sample comprised 433 adult RTI patients, admitted to the emergency department (ED) of a public hospital in Mexico City (January to April 2022). Breath Alcohol Concentration (BAC) was measured using a breath tester, and six types of drugs (amphetamines, barbiturates, benzodiazepines, cannabis, cocaine, and methamphetamine) were assessed using a saliva screen test. RTI patients also self-reported their alcohol and drug use in the six hours prior to the accident. Approximately 62% of respondents had been involved in a motorcycle crash. One in three patients self-reported or had traces of a substance in their saliva or breath. The most common substance was alcohol (23.6%), followed by cannabis and stimulants (10.9%). One in five patients reported having used a cell phone ten minutes before the injury. One in three had not been using any safety device, the only behavior exacerbated by substance use. We found a high prevalence of substance use in the sample of RTI patients admitted to the ED, regardless of the type of the RTI, together with high cell phone rates. Motorcycle passengers under the influence were particularly likely not to have been wearing a helmet.