How is drug dependence defined?

• A. Temporary mood change after one use
• B. Physical dependence on all drugs
• C. Tolerance to all drugs
• D. A condition where the body develops a chemical need for a drug and cannot function normally without it

Answer: (D)

Dependence means the body has adjusted to a drug to the point that it “needs” the drug to function normally. This chemical adjustment, or adaptation, can lead to withdrawal symptoms if the drug is reduced or stopped, making continued use feel necessary to avoid those negative effects. That’s why this option best matches the true definition.

A describes a short-lived, immediate effect after one use, not dependence. B is too broad—not every drug causes physical dependence in everyone. C describes tolerance, which is about needing more of the drug to get the same effect, but it isn’t the full definition of dependence (though tolerance can be part of the picture).