Final answer:
Withdrawal is the term for the need for increased amounts of a substance to achieve the desired effect with continued use. It is a symptom of physical dependence and can occur with alcohol or drugs. Tolerance, on the other hand, refers to needing more of a drug to achieve previous effects.
Step-by-step explanation:
Withdrawal is the correct term for the need for markedly increased amounts of alcohol or a drug to achieve the desired effect or a markedly diminished effect with continued use of a substance. It is a symptom of physical dependence, which occurs when a drug user requires more and more of a given drug in order to experience the same effects. Tolerance, on the other hand, is linked to physiological dependence and refers to the need for increasing amounts of a drug to achieve previously experienced effects.