Individual Differences in Reward and Impulse Control

Background: Even under similar drug use patterns, the risk for drug addiction varies from individual to individual. However, the neurobiological mechanisms underlying this variability are poorly understood and characterized. Studies suggest that certain traits observed in substance dependent individuals may actually precede drug use, and could augur future substance dependence. Understanding how the presence of these traits increases vulnerability to substance addiction could aid in the development of early intervention, preventative measures, as well as better treatment strategies. Objective: The primary goal of this protocol is to improve our understanding of increased susceptibility to developing substance addiction. We focus here on particular gene x environment interactions as increased risk factors for substance dependence. The emphasis is on monoaminergic neurotransmitter-related genes thought to influence adaptability to the environment, and, therefore, on cognitive domains related to dopamine and serotonin: reward and punishment learning, and impulse control. To achieve the above objective, the study will be implemented by using cognitive, genetic and neuroimaging testing in adult addicted individuals along with matched controls. Subject Population: We focus on adult (18-55 years old) smokers and matched non-smoking controls. Experimental Design: This study involves cognitive, pharmacological and functional magnetic resonance imaging (fMRI) testing in a between-subject design involving neuroimaging and cognitive testing. Outcome Measures: The primary outcome measures will be BOLD fMRI activation and behavioral performance on various cognitive tasks that deal with impulse control and reward learning, as a function of gene x environment interactions.