ABSTRACT
In this chapter we examine the evidence for specific ingredients—are the purported ingredients of an effective treatment responsible for the benefits of the treatment? The most direct way to examine the importance of a specific ingredient is in a component study, in which a critical ingredient is removed from an existing treatment or a component is added to an existing treatment to determine the effects of the deleted or added component. Next, designs that attempt to use some type of “placebo” control to examine the specific effects are reviewed, but it will become apparent that these placebo-type designs are inadequate for this purpose. Then, designs that attempt to match treatments to patients with a particular psychological deficit are reviewed. We also examine adherence and competence, as these are important auxiliaries in the Medical Model related to specific ingredients. Finally, we will look at attempts to identify mediating processes for specific treatments, including adherence to the treatment protocol, although there have been few attempts to synthesize this literature, which makes it difficult to present.
