What does "tolerance" refer to in substance dependence?

The concept of "tolerance" in substance dependence specifically refers to the phenomenon where an individual requires a progressively larger amount of a substance to achieve the same effect that was once obtained with a smaller dose. This change occurs because the body adapts to the presence of the substance, leading to diminished responsiveness to its effects over time. As a result, the individual may find themselves needing to consume more of the substance in order to experience its effects, which can contribute to the cycle of dependence and increase the risk of substance use disorders.

The other options do not accurately represent the concept of tolerance. The absence of physical symptoms relates more to the state of withdrawal or overall dependence, while safe use practices are aimed at reducing risks rather than addressing the physiological adaptations associated with chronic substance use. Lastly, the ability to stop using without withdrawal symptoms pertains to a person's level of physical dependence but does not capture the essence of tolerance itself. Understanding tolerance is crucial for recognizing how addiction develops and progresses, informing treatment strategies for individuals facing substance use challenges.