What behavior does being under the influence of a controlled substance refer to?

Being under the influence of a controlled substance refers specifically to willfully using or being influenced by substances that are classified as controlled under law. This includes not just illegal drugs but also substances that may be legal under certain conditions, such as prescription medications, when they impair a person's ability to function normally.

This definition encompasses a broad spectrum of substances beyond just alcohol or prescription medications. While intoxication and driving under the influence are important concerns, they represent specific scenarios rather than a comprehensive understanding of what it means to be under the influence of controlled substances. The focus on willful usage underscores the intentionality behind consuming these substances and recognizes that their effects can vary widely among individuals.