What is the definition of drug abuse?

The definition of drug abuse focuses on the misuse of substances in ways that are not aligned with their intended purpose, leading to harmful consequences. When someone uses a substance in a manner not intended or prescribed, it often results in negative health effects, dependency, or other problems. This definition encompasses various forms of misuse, including using a drug in excess, for non-medical reasons, or using someone else's prescription.

The other options define responsible or appropriate use of substances. Using a substance within prescribed limits or solely for medical purposes highlights proper usage, while using medication as advised by a doctor emphasizes adherence to medical guidance. These contexts do not align with the definition of drug abuse, which specifically addresses misuse and its potential impacts.