Which statement best differentiates tolerance from dependence?

Which statement best differentiates tolerance from dependence?

• A. Tolerance means needing a larger dose for the same effect; dependence means a chemical need and inability to function normally without the drug.
• B. Tolerance means withdrawal symptoms disappear; dependence means nothing changes.
• C. Tolerance is the same as dependence; both mean you can't function without the drug.
• D. Tolerance occurs only with illegal drugs; dependence only with prescription drugs.

Answer: (A)

The main idea here is that tolerance and dependence describe different changes in how the body responds to a drug. Tolerance means the body adapts to regular use, so you need a larger dose to achieve the same effect because the drug’s impact diminishes with continued exposure. Dependence means the body has become so used to the drug that it relies on it to function normally; if you stop taking it, withdrawal symptoms or disruptions in functioning can occur. The statement that best differentiates them combines these two ideas: you need a larger dose for the same effect (tolerance), and there is a chemical need and an inability to function normally without the drug (dependence). The other options misstate either what tolerance or dependence involve, or wrongly claim these phenomena are limited to illegal vs. prescription drugs.

The main idea here is that tolerance and dependence describe different changes in how the body responds to a drug. Tolerance means the body adapts to regular use, so you need a larger dose to achieve the same effect because the drug’s impact diminishes with continued exposure. Dependence means the body has become so used to the drug that it relies on it to function normally; if you stop taking it, withdrawal symptoms or disruptions in functioning can occur. The statement that best differentiates them combines these two ideas: you need a larger dose for the same effect (tolerance), and there is a chemical need and an inability to function normally without the drug (dependence). The other options misstate either what tolerance or dependence involve, or wrongly claim these phenomena are limited to illegal vs. prescription drugs.