Individual Differences in Reward and Impulse Control
Condition: Drug Addiction; Vulnerability to Substance Addiction
MeSH terms: Substance-Related Disorders; Behavior, Addictive
Study type: Observational

Summary: 
      Background:

      - The risk for becoming addicted to drugs varies among individual, even those using similar
      drugs in a similar way. It is not known why some people become addicted and others do not.
      Studies suggest that some genes may increase the risk of addiction. Negative life experiences
      may also affect the risk of addiction. Researchers want to test smokers and nonsmokers to
      study genetic and brain function traits that may lead to drug addiction.

      Objectives:

      - To understand brain function in people who may be at a higher risk of drug addiction.

      Eligibility:

        -  Healthy volunteers between 18 and 55 years of age.

        -  Smokers (10 to 30 cigarettes per day for more than 2 years) and nonsmokers will be
           eligible.

      Design:

        -  Participants will be screened with a physical exam and medical history. They will be
           tested for drug and alcohol use. A blood sample will be collected.

        -  The study will involve one visit. Participants will have a magnetic resonance imaging
           (MRI) scan.

        -  At the visit, participants will answer questions about their health and drug use habits.
           They will then be trained on the tasks they will do during the MRI scan. After the
           training, they will have the scan and perform the tasks. The scan and tasks will look at
           brain function related to rewards and impulsiveness.

        -  Other computer tests will be given after the scan. These tests will measure learning,
           memory, and impulsiveness.
    

Detailed description: 
      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.
    

Time perspective: Retrospective
Keywords: fMRI; Monoamines; Environment; Genes; Reward Learning