How should addictive behavior be explained? In terms of neurobiological illness and compulsion, or as a choice made freely, even rationally, in the face of harmful social or psychological circumstances? Some of the disagreement between proponents of the prevailing medical models and choice models in the science of addiction centres on the notion of “loss of control” as a normative characterization of addiction. In this article I examine two of the standard interpretations of loss of control in addiction, one according (...) to which addicts have lost free will, the other according to which their will is weak. I argue that both interpretations are mistaken and propose therefore an alternative based on a dual-process approach. This alternative neither rules out a capacity in addicts to rationally choose to engage in drug-oriented behavior, nor the possibility that addictive behavior can be compulsive and depend upon harmful changes in their brains caused by the regular use of drugs. (shrink)