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Chapter 5: Psychopharmacology and New Drug Development

Terms in this set (52)

A type of functional tolerance that occurs within a course of action of a single drug dose

-d. Acute tolerance (sometimes called tachyphylaxis) is measured within the course of action of a single dose or the first few doses of a drug. When a person takes a dose of a drug, the amount of drug in the body—measured as the amount of drug in the blood, or the blood level—rises to some peak level.

-With some drugs, at any point when the blood level is rising to peak, users may experience greater drug effects than at that same point when the blood level is falling.

ex./For example, people show acute tolerance to alcohol. One effect of alcohol when consumed in moderate amounts is impairment in speed of performance of cognitive tasks (generally, tasks that require functions like memory, decision making, and problem solving, for example).

-Because of acute tolerance to alcohol, we are more likely to see impairment in the speed with which we perform cognitive tasks when the blood level of alcohol is rising than when it is falling. Interestingly, this same acute tolerance effect does not hold for the accuracy of performance

ex./A second example of acute tolerance is with regard to stimulant drugs like cocaine. Cocaine is a short-acting drug, and when the highly pleasurable effects of an initial dose begin to wear off, users are prone to taking another dose. However, the second administration—even when the same amount is taken—generally produces much less of a pleasurable high due to rapidly developing acute tolerance
1. Indeed, one study used brain-imaging techniques to show that the administration of a placebo to participants who expected to receive a painkiller drug may result in chemical changes in the CNS that follow those induced by actual painkillers.

-In their review of the literature, Finniss et al. (2010) described similar neurobiological changes resulting from the administration of placebo drugs in the treatment of, for example, Parkinson's disease and depression.

-Therefore, in many experiments, the effects of administration of an actual chemical compound of interest can be specified only by comparing conditions in which people are told that they receive a drug, and then half actually get a chemically active substance and half do not.

2. Sometimes all the experimental participants are told that they may or may not receive the real drug and then half really get the drug and half do not. In either case, neither the experimenter nor the participant knows whether the drug or placebo is administered to any one participant.

-This "double- blind" method is used so that biases from the experimenter or participant, according to their respective beliefs and expectancies about the drug or the experimental situation in general, are less likely to affect the results of the study.

ex./ For example, a person who takes the drug may have specific expectancies about what effects it will have. Similarly, a person who administers the drug may have expectancies about its effects and accordingly may react to a person receiving the drug in a certain way.

-Both the participant's and the experimenter's expectancies may influence the effects of the drug that the participant experiences. Even professionals who are skeptical about whether a person's expectancies can affect the response to a medication agree that placebo controls are needed in drug research