PET Assays of Striatal Dopamine Marker in Cocaine Craving
Condition: Neural Systems; Drug Abuse; Cocaine Dependence
MeSH terms: Cocaine-Related Disorders; Substance-Related Disorders
Study type: Observational

Summary: 
      Background:

        -  Cues related to past drug use induce a particular pattern of brain activation, which has
           been correlated with craving for cocaine in active cocaine abusers. Researchers are
           interested in determining the role of the brain chemical dopamine in cue-elicited as
           well as spontaneous craving for cocaine.

        -  To study the role of dopamine in cocaine craving, researchers will use positron emission
           tomography (PET) to compare the neural reactions of cocaine users with those of
           non-substance-abusing healthy volunteers. Researchers hope that the data gathered from
           this study will lead to the development of more effective anti-craving medications.

      Objectives:

        -  To clarify the role of dopamine in cue-elicited responses that contribute to cocaine
           abuse.

        -  To determine if PET results of this study differ with various means of administering PET
           chemicals.

      Eligibility:

      - Individuals 21 to 44 years of age who are either current cocaine users (at least twice per
      week) or healthy volunteers without a history of drug abuse.

      Design:

        -  Cocaine-using participants will enter the inpatient clinical research ward at the
           National Institute on Drug Abuse (NIDA) Addiction Research Center for 2 nights before
           the day of the study. In addition, these participants will stay overnight at NIDA the
           evening after each PET session and will be discharged the following day. Cocaine-using
           participants will be required to perform a balance test before the study to provide a
           baseline response in case they require anti-anxiety medications to cope with the effects
           of the study.

        -  Control subjects will not be required to stay overnight and will arrive as outpatients
           for the PET session. All participants will be required to abstain from alcohol and
           caffeine consumption from midnight before each study session, and will not be permitted
           to smoke on the day of testing.

        -  - On the day of the study, participants will undergo a practice session to set up the
           PET scanning equipment. Following the practice session, participants will be shown video
           recordings of images that are related to nature (e.g., seashells) or to drug abuse
           (e.g., drug paraphernalia). Participant reactions will be studied through the PET
           monitoring, and the study will be conducted in two separate PET sessions with a break in
           between. Individuals in the cocaine-using group may receive anti-anxiety medication if
           the stimulus cues increase anxiety related to cocaine craving.

        -  Different groups of participants will receive different methods of PET chemical
           administration, and researchers will compare these methods.
    

Detailed description: 
      Cues related to past drug use induce a particular pattern of brain activation, which has been
      correlated with craving for cocaine in active cocaine abusers. The proposed research is
      designed to assess the role of dopamine in cue-elicited as well as spontaneous craving for
      cocaine. Cocaine abusers and control subjects will be presented with a stimulus complex
      related to drug abuse (cocaine cues: videotape depicting drug use, drug paraphernalia) or to
      nature (neutral cues: videotape depicting items such as shells and pinecones). The effects of
      each cue condition on striatal D2-like dopamine (DA) receptors and changes in intrasynaptic
      dopamine will be measured by positron emission tomography (PET). The PET data will then be
      correlated with subjective self-reports of mood, particularly measures of craving. These
      results will be compared between the two subject groups. This research will help clarify the
      role of dopamine in cue-elicited responses that contribute to cocaine abuse. Ultimately, the
      results obtained may lead to the development of anti-craving medications.
    

Time perspective: Prospective
Keywords: Drug Cues; Dopamine Release; Psychomotor Stimulants; D2 Dopamine Receptor Subtype; Neuroimaging