How is tolerance defined in substance use?

• A. Withdrawal symptoms upon cessation
• B. Craving after abstinence
• C. Increased energy after a dose
• D. Higher dose required to achieve the same effect

Answer: (D)

Tolerance is the diminished response to a drug after repeated use, so a higher dose is needed to achieve the same effect as before. This happens because the body adapts—metabolic changes may break down the drug more quickly, or neural adaptations reduce the drug’s impact at its target receptors. That’s why the statement about needing a larger dose to obtain the same effect best captures the idea of tolerance.

Withdrawal symptoms upon cessation reflect the opposite process—the body reacting to the absence of the drug. Craving after abstinence is about a renewed urge to use, not a diminished drug effect. Increased energy after a dose describes the drug’s immediate effect, which can occur regardless of tolerance and isn’t the definition of tolerance itself.