A review of cross-commodity delay discounting research with relevance to addiction.

Delay discounting (DD) refers to the decrease in the subjective value of a reward as the delay to its receipt increases. As high rates of DD are consistently associated with measures of substance misuse, DD is an important construct in current conceptualizations of addiction. High rates of DD appear to model preference for the immediate rewards provided by substance use, resulting in the interpretation that individuals with substance use disorder are generally unable or unwilling to delay gratification to obtain larger but delayed rewards. This interpretation is largely based on literature implementing binary choice tasks using differing amounts of the same commodity (i.e., single-commodity), in which high rates of DD can result from relative preference for the immediate outcome or relative dispreference for the delayed outcome. We propose that tasks using different commodities (i.e., cross-commodity) for the immediate and delayed outcomes offer potential in disentangling these dissociable and consequentially distinct interpretations. Our review suggests that cross-commodity DD tasks provide unique insights into understanding addiction not captured by single-commodity designs. We conclude that more research implementing cross-commodity DD tasks is needed to better understand the role of intertemporal choice in addiction and recovery.