Addiction: the belief oscillation hypothesis

In popular, philosophical and many scientific accounts of addiction, strong desires and other affective states carry a great deal of the explanatory burden. Most of the drug procuring and consuming behaviour of addicts is entirely normal, in the following sense: it gives every appearance of being what psychologists call controlled behaviour, or of being explicable by what philosophers call belief/desire or folk psychology. Central to the addiction phenotype, however, is the response of the midbrain dopamine system to drugs of addiction. Addicted people remain rational agents. They are not simply at the mercy of subpersonal mechanisms that cause representational states to change without apparent reason. Most people – laypeople and specialists alike – regard addiction as causing or constituting pathology of control over behaviour. The chapter suggests that the failure of the midbrain dopamine system to adapt to the reward value of addictive drugs provides a mechanism for such dramatic judgment-shifts.