Adaptations of the reward circuit to intermittent and chronic supraphysiological stimulation by drugs increase reward thresholds. As a consequence, response to non-drug reinforcers in individuals with chronic drug use or addiction, may be decreased. Clinical symptoms include anhedonia and compulsive drug use, at the expense of the attainment of other rewarding experiences and despite detrimental consequences to the individual's functioning. While most addiction studies focus on the increased valuation of drug reward and drug-related cues, this chapter instead reviews the behavioural and...

Adaptations of the reward circuit to intermittent and chronic supraphysiological stimulation by drugs increase reward thresholds. As a consequence, response to non-drug reinforcers in individuals with chronic drug use or addiction, may be decreased. Clinical symptoms include anhedonia and compulsive drug use, at the expense of the attainment of other rewarding experiences and despite detrimental consequences to the individual's functioning. While most addiction studies focus on the increased valuation of drug reward and drug-related cues, this chapter instead reviews the behavioural and neurobiological evidence for decreased valuation of non-drug reinforcers and cues. Future research should directly address the following question: is processing of drug reward enhanced at the expense of non drug-related reward (at least in certain subgroups of addicted individuals)? Or are these two processes independent?