Grant: CIHR Fellowship

The majority of individuals try potentially addictive drugs (e.g., alcohol, nicotine) at some point in their life. Only a small number of them, however, move from recreational use to compulsive and excessive use that is characteristic of addiction. Furthermore, even following long periods of abstinence, addicted individuals often relapse. In fact, relapse occurs in vast majority of addicted individuals and it represents the greatest challenge in the treatment of addiction. Experimental and clinical evidence suggests that cues or stimuli associated with drug use (e.g., cigarette smoke, a wine glass, needles, etc.) can themselves acquire motivational properties, and thus spur motivation or craving for the drug and increases the likelihood of relapse. Importantly, there are significant individual differences in the degree to which drug-cues can trigger drug craving. Human positron emission topography studies, as well as preclinical evidence from rat studies, indirectly suggest that brain neurotransmitter dopamine (DA) levels are correlated with cue-evoked drug craving. In the current project we propose to assess the relationship between the propensity to attribute motivational value to a drug cue (individual differences in attraction to drug-cues), DA concentrations, and the tendency to relapse to drug seeking. We hypothesize that relapse can be predicted by observing how attracted individuals are to drug-cues and drug-cue evoked DA release. We will use novel and advanced technology (fast-scan cyclic voltammetry), capable of measuring sub-second changes in DA transmission (real-time DA). Given that there are great individual differences in susceptibility to addiction and that these differences are poorly understood, the proposed pre-clinical experiments are of great importance. Our results will advance our theoretical understating about addiction as well as interventions and treatments for drug addiction.