What is the most commonly used federally illicit drug in the U.S.?

Cannabinoids, particularly THC, a component of marijuana, are the most commonly used federally illicit drug in the U.S. Despite the increasing legalization of cannabis in many states, it remains classified as a Schedule I substance under federal law, making its use illegal at the federal level. This classification and the widespread popularity of marijuana contribute to its status as the most frequently used illicit drug nationally.

The history of cannabis use in the U.S., the cultural acceptance, and the prevalence in various demographics further emphasize its significant consumption rates compared to other drugs listed. Factors such as social attitudes toward marijuana and its availability in legal markets in several states influence its commonality of use.

In contrast, cocaine, heroin, and MDMA have lower user populations compared to the widespread use of cannabis, primarily due to societal acceptance and legal issues surrounding those substances. While each of these drugs poses significant risks and harms, their usage is not as widespread as that of cannabinoids, solidifying cannabis's position as the most commonly used federally illicit drug.