Drug use increases the risk of illness, accidents, and premature death. Drug dependence increases exposure to health risks (infection, overdoses, mental health disorders, etc.) and social risks (precarious living conditions, social exclusion, etc.). Polydrug use increases health risks. It is common among illicit drug users (IDUs) other than cannabis users, with some combining drugs with medications (benzodiazepines, substitution therapy, etc.).

Drug use can occur across all social backgrounds, and patterns range from recreational use to addiction, encompassing various substance use disorders. Cannabis is the most commonly used illicit drug. It has a generally positive image among young people, who are particularly vulnerable to the toxicity of this substance.

In recent years, cocaine use has been on the rise, while crack continues to spread among vulnerable populations as well as among younger users who refer to it as “freebase.” A trend toward the reemergence of heroin is observed among novice users and in party settings.