Marc Lewis argues that addiction is not a disease, it is instead a dysfunctional outcome of what plastic brains ordinarily do, given the adaptive processes of learning and development within environments where people are seeking happiness, or relief, or escape. They come to obsessively desire substances or activities that they believe will deliver happiness and so on, but this comes to corrupt the normal process of development when it escalates beyond a point of functionality. Such ‘deep learning’ emerges from consumptive (...) habits, or ‘motivated repetition’, and although addiction is bad, it ferments out of the ordinary stuff underpinning any neural habit. Lewis gives us a convincing story about the process that leads from ordinary controlled consumption through to quite heavy addictive consumption, but I claim that in some extreme cases the eventual state of deep learning tips over into clinically significant impairment and disorder. Addiction is an elastic concept, and although it develops through mild and moderate forms, the impairment we see in severe cases needs to be acknowledged. This impairment, I argue, consists in the chronic automatic consumption present in late stage addiction. In this condition, the desiring self largely drops out the picture, as the addicted individual begins to mindlessly consume. This impairment is clinically significant because the machinery of motivated rationality has become corrupted. To bolster this claim I compare what is going on in these extreme cases with what goes on in people who dissociate in cases of depersonalization disorder. (shrink)