Internal Stimuli Generated by Abused Substances: Role of Pavlovian Conditioning and Its Implications for Drug Addiction

Consideration of the importance of Pavlovian conditioning involving interoceptive stimuli to health-related issues dates back to Pavlov. Despite this long history and its likely importance, the preponderance of empirical and theoretical effort in the drug abuse field has been on exteroceptive conditioning with the drug conceptualized as the unconditioned stimulus. This chapter reviews what research has been done on Pavlovian conditioning involving the interoceptive effects of abused drugs as stimuli (i.e., conditioned stimuli or occasion setters). That research indicates that conditioning not only alters behavior evoked or modulated by drug stimuli, but that it alters the drug state in a manner that likely contributes to addiction. For instance, nicotine and diazepam acquire conditioned reinforcing value by virtue of being repeatedly paired with an appetitive event. Throughout the chapter we highlight translational links between preclinical research on interoceptive drug stimuli and drug addiction, as well as identify gaps in the scientific literature.