The incentive salience of alcohol - Translating the effects of genetic variant in CNR1

Context: The gene that codes for cannabinoid receptor 1 (CNR1) represents an important target for investigations designed to elucidate individual differences in the etiology of alcohol dependence. Objective: To achieve a better understanding of the role of the CNR1 gene in the etiology and treatment of alcohol dependence. Design: The present investigation spans multiple levels of analysis, including receptor binding in postmortem brain tissue, neuroimaging, human laboratory models, and analyses of treatment outcome data. Results: Findings indicate that the C allele of rs2023239 is associated with greater CB1 binding in the prefrontal cortex, greater alcohol cue - elicited brain activation in the midbrain and prefrontal cortex, greater subjective reward when consuming alcohol, and more positive outcomes after treatment with a medication that targets the mesocorticolimbic neurocircuitry. In addition, there were strong correlations between cue-elicited brain activation and alcohol consumption measures in individuals with the C allele. Conclusion: Individuals with the C allele may be more susceptible to changes in the mesocorticolimbic neuro-circuitry that is involved in the attribution of incentive salience after repeated exposure to alcohol.