What is the main characteristic of tolerance in substance use?

Tolerance in substance use primarily refers to the phenomenon where an individual requires a higher dose of a substance to achieve the same effect that was initially experienced with a lower dose. This occurs because the body adapts to the presence of the substance, leading to a decrease in its responsiveness. Over time, as substance use continues, the body becomes accustomed to the substance's effects, causing the individual to consume more to feel the desired effects. This characteristic is a critical component in understanding substance use disorders and is crucial for assessing and treating individuals with dependencies.

Psychological dependence, increased withdrawal symptoms, and reduced efficacy of treatment do relate to substance use and dependence, but they reflect different aspects of the experience rather than the specific process of tolerance itself.