An initial one-amphetamine dose that becomes less effective as tolerance develops is an example of:

An initial one-amphetamine dose that becomes less effective as tolerance develops is an example of:

• A. Withdrawal
• B. Tolerance
• C. Resistance
• D. Dependence

Answer: (B)

The idea being tested is tolerance: when a drug is used repeatedly, the body adapts so the same dose produces a smaller effect. With an initial one-amphetamine dose, as tolerance develops the brain adjusts—receptors may become less responsive and signaling pathways may downregulate, or the body may up its metabolism—so that the same amount no longer feels as strong. To get the same level of stimulation, a larger dose may be needed, which is the hallmark of tolerance. This differs from withdrawal (symptoms that appear when stopping the drug) and from dependence (a broader pattern of needing the drug to function and to avoid withdrawal), and the term resistance isn’t the standard way to describe this pharmacological change.

The idea being tested is tolerance: when a drug is used repeatedly, the body adapts so the same dose produces a smaller effect. With an initial one-amphetamine dose, as tolerance develops the brain adjusts—receptors may become less responsive and signaling pathways may downregulate, or the body may up its metabolism—so that the same amount no longer feels as strong. To get the same level of stimulation, a larger dose may be needed, which is the hallmark of tolerance. This differs from withdrawal (symptoms that appear when stopping the drug) and from dependence (a broader pattern of needing the drug to function and to avoid withdrawal), and the term resistance isn’t the standard way to describe this pharmacological change.