“…Different designs use points for rewards [111,112], pictures of rewards [7,[113][114][115][116][117] or consumption of rewards [14,[118][119][120][121][122][123][124]. Preferential drug choice is reliably associated with the severity of dependence to heroin [125], cocaine [116,117,126,127], alcohol [10,15,26,112,113,115], and tobacco [15,111,114,124,128]. These associations have been found in both clinical [15,113,114,116,117,[125][126][127] and non-clinical samples [10, 26, 111-113, 115, 128].…”