Dissociation of wanting and liking for alcohol in humans: a test of the incentive-sensitisation theory

Rationale: Incentive sensitisation theory (IST) claims that the mechanism of reward is comprised of separate neurobiological systems of wanting and liking, that dependent drug use occurs as a result of sensitisation of the system controlling wanting, and that the two systems can be dissociated. Objective: To test the IST prediction that wanting and liking for alcohol can be dissociated in humans. Methods: Measures of wanting and liking for alcohol were obtained in three experiments. Experiment 1 examined whether liking for alcohol was associated with levels of wanting, as indexed by self-reported weekly alcohol intake. Experiments 2 and 3 also assessed the association between liking and wanting but in these experiments wanting was also indexed by alcohol consumption in the laboratory. Experiment 2 increased wanting for alcohol using an alcohol priming dose to determine whether liking would be similarly affected. Experiment 3 reduced liking for alcohol by adulterating drinks with Tween to see whether wanting would also be reduced. Results: Little evidence for an association between liking and wanting for alcohol was found in Experiments 1-3 but, collapsing across all experiments, a weak positive correlation between liking and wanting was found. However, in Experiment 2. wanting was increased by the alcohol priming dose whereas liking was not and in Experiment 3 liking was reduced without a concurrent reduction in wanting. Conclusions: Although correlations between wanting and liking can be observed these results support the contention of the IST that wanting and liking for alcohol can be dissociated in human participants.