The enhanced motivation to procure drugs is a hallmark of addiction, and this is well captured on the “incentive salience” hypothesis of addiction. This hypothesis proposes that, in addiction, drugs acquire enhanced “incentive salience” whereupon the drugs are consumed, not because they are liked (hedonic value), but because they are “wanted” (incentive value of reward) (66). In fact, the decrease in subjective responses to drugs along with the reduced drug-induced increases in DA support the notion that the motivation to procure drugs is not driven by drug “liking” but rather by an enhanced motivational drive to procure them. Indeed, drug-addicted individuals will go to extreme behaviors to obtain drugs even at the expense of seriously adverse consequences (2). In an addicted person, drug seeking and drug taking become the main motivational drives displacing all other activities (67). As a result, the addicted person is aroused and motivated when seeking to procure the drug and lacks motivation to pursue non-drug-related activities.
