Final answer:
The correct term for when a drug user needs to increase the drug amount to achieve the same effects is 'tolerance'. Tolerance signifies a diminished response to a drug due to prolonged exposure, differentiating it from withdrawal symptoms and psychological dependence. So the correct answer is option (A).
Step-by-step explanation:
The term that describes the state of adaptation induced by drug exposure that results in the diminishment of one or more of the drug's effects over time is tolerance. Tolerance occurs when a drug user requires more and more of a given drug to experience the same effects they once felt at lower doses. This can potentially lead to dangerous situations, such as overdose, as the user may consume increasingly larger amounts of the substance.
In contrast to tolerance, withdrawal refers to the variety of negative symptoms experienced upon discontinuation of drug use, and drug craving relates to psychological dependence. Addiction, or drug addiction, denotes the compulsive use of a substance despite negative consequences.