How do you know you have a drug problem? The role of knowledge of negative consequences in explaining drug choice in humans and rats

Choice models of addiction raise a stark puzzle. Why, if addicts are able to control their consumption and choose to abstain in many circumstances, do they routinely choose to continue to use despite negative consequences? We delineate four options available to a choice theorist to explain this puzzle with respect to human addicts; describe recent experiments with addicted rats which determine the conditions under which they do and do not choose alternative goods over cocaine and heroin respectively; and consider how this animal research bears on our understanding of the nature of addiction. We conclude by arguing for the importance to addiction research of the popular notion of ‘denial’ which, paradoxically, we can begin to theorize by appeal to animal models: for the puzzle dissolves if addicts do not know that the choice to use is the cause of negative consequences, as rats, given their cognitive limitations, cannot.