“…Although addicts retain the capacity to refrain from use in many circumstances (see Section 1), there is no question that the desire for drugs characteristic of addiction is very strong and hard to resist (Robinson and Berridge, ; Holton and Berridge, ; Segal, ); and, moreover, for many addicts, drugs additionally serve valuable functions (Muller and Schumann, ; Pickard, and forthcoming) as well as offering pleasure (Foddy and Savulescu, , ). Despite the costs, addicts are nonetheless strongly motivated and highly incentivized to continue to use drugs.…”