ABSTRACT
This chapter focuses on psychological functioning and performance. It reviews literature concerned with underlying physiological effects and attempt to integrate knowledge under a biobehavioral model. In the context of the biobehavioral theory, the relationship between caffeine and psychological functioning appears to be quite straightforward. Caffeine is undoubtedly the most widely consumed of all psychotropic drugs. In addition to coffee and tea, the psychological effects of caffeine can be obtained from a number of other food sources. The multi-source availability of caffeine means that investigators studying total consumption must be exceptionally careful to query subjects concerning all possible sources in their dietary and drug intakes. The arousal component of the dual-interaction model, which governs the effects of caffeine, can be split out and amplified to provide a multi-dimensional model of arousal. Information-processing theory has served as the basis for a number of studies of the effects of caffeine on cognitive functioning.
