What is a key characteristic of tolerance in relation to drug use?

Tolerance refers to the phenomenon where a person's response to a drug diminishes with repeated use, leading them to require a larger amount of the substance to achieve the same effect that was previously attained with a smaller dose. This adaptation occurs because the body becomes accustomed to the drug, resulting in changes in metabolism or receptor sensitivity. Therefore, as tolerance develops, an individual finds that they need to increase their dose to experience the desired effects, which highlights the characteristic nature of tolerance in relation to drug use.

In contrast, loss of interest in activities is more indicative of psychological effects like those seen in addiction or dependence, rather than tolerance itself. The ability to endure side effects may relate to individual variation but does not specifically define tolerance. Lastly, although withdrawal symptoms can be a part of drug dependence, the presence or negligible nature of these symptoms does not characterize tolerance directly. Thus, the need for an increased amount of the drug to achieve the same effect is the essence of tolerance.