Effects of Nicotine on Areas of Impaired and Preserved Functioning in Schizophrenia
Condition: Nicotine Dependence; Schizophrenia
MeSH terms: Tobacco Use Disorder; Schizophrenia
Study type: Observational

Summary: 
      Background:

        -  Some people with schizophrenia have problems with their working memory and paying
           attention for extended periods. These difficulties cannot be treated with antipsychotic
           medications or with many standard therapies.

        -  The prevalence of cigarette smoking among individuals with schizophrenia is about three
           times higher than in the general population. Research has shown that nicotine, the
           addictive component found in cigarettes, can help improve attentional and working memory
           performance. Researchers are interested in learning more about whether there may be an
           overlap in the cognitive functions beneficially affected by nicotine and areas of
           dysfunction in individuals with schizophrenia.

      Objectives:

        -  To evaluate the potential of transdermal nicotine to alleviate cognitive deficits in
           schizophrenia, and to determine whether naturally maintained cigarette-smoking, in
           comparison, is an effective self-medication.

        -  To gather preliminary data on genetics that may account for individual and group
           differences in the performance effects of nicotine.

      Eligibility:

      - Current smokers (25 or more cigarettes per week for at least 1 year) between 18 and 55
      years of age who are either healthy volunteers or have been diagnosed with
      schizophrenia/schizoaffective disorder.

      Design:

        -  The study will require five visits to the research center, with an initial screening
           visit, a training session, and three test sessions. Ideally, all visits will occur 1
           week apart.

        -  Training session: Participants will receive training on the types of computerized
           cognitive and attentional behavior tests that will be given during the active portion of
           the study. Participants will also fill out questionnaires on nicotine use and other
           alcohol and drug use.

        -  Test sessions: Participants will be assigned to random groups and will complete tests
           that assess cognitive performance (a) while maintaining their usual smoking behavior,
           (b) after minimal deprivation (3.5 hours without smoking) while wearing a placebo patch,
           and (c) under the influence of a standard nicotine patch. The order of these sessions
           will be different for individual participants.

        -  Participants will provide blood samples throughout the research study for evaluation
           purposes.
    

Detailed description: 
      Objective:

        1. To evaluate the potential of transdermal nicotine to alleviate distinct cognitive
           deficits in schizophrenia, and to determine whether naturally maintained
           cigarette-smoking, in comparison, is an effective self-medication.

        2. To gather preliminary data on genotypes that may account for interindividual and group
           differences in the performance effects of nicotine.

      Study population:

      45 regular smokers with schizophrenia, 45 matched control smokers (greater than or equal to 5
      cigarettes/day).

      Design:

      Double-blind, placebo-controlled, within-subject study, evaluating cognitive functions under
      conditions of normal smoking, transdermal nicotine (14 mg/day), and placebo (minimal tobacco
      deprivation).

      Outcome measures:

      Measures of cognitive task performance, measures of subjective state, plasma concentrations
      of nicotine and metabolites, and genotype with regards to genes coding for nicotinic receptor
      subunits, MAO, and COMT.
    

Time perspective: Other
Keywords: Nicotine; Schizophrenia; Cognition; Genes; Smoking; Cigarette Smoking