Improving Cognition in Schizophrenia Using tDCS
Condition: Schizophrenia
MeSH terms: Schizophrenia
Study type: Interventional

Summary: 
      This study will examine the benefits of transcranial direct current stimulation (tDCS), a new
      tool that is being developed as a safe and non-invasive neurostimulation method, for
      improving neurocognitive and social cognitive functions in schizophrenia. This procedure is
      non-invasive and painless and it results in increase or decrease of spontaneous neuronal
      firing in the brain. Its safety and beneficial effect on cognition has been demonstrated in
      healthy individuals and several clinical populations. In this pilot study, the investigators
      will examine the effect of tDCS on cognitive functions in 40 individuals with schizophrenia.
      Each participant will arrive for three visits, with approximately one week between each
      visit. During the first visit, participants will be interviewed about their psychiatric
      symptoms, personal life experiences, and emotional well being by a specially-trained
      interviewer. On each of the three visits, participants will receive one of three
      stimulations: a type of tDCS designed to increase neuronal firing, an alternative form of
      tDCS designed to decrease neuronal firing, and a sham tDCS (stimulation with no current).
      Immediately following the stimulation, participants will be asked to complete measures of
      mental abilities, including tests presented on a computer screen and paper-and-pencil tests.
      During each visit, participants will also undergo a standard measure of brain activity (EEG)
      while listening to tones. The first visit will last approximately five hours, and the other
      two visits will last approximately four hours each. The project will take approximately two
      years to complete.
    

Detailed description: 
      The investigators plan to recruit 40 individuals diagnosed with Schizophrenia. Participants
      will range from 18-55 years old. We will select stable, medicated patients who have not been
      hospitalized nor had any changes in their antipsychotic medications during the previous two
      months. Participants will not be tested within 12 hours of taking medications that may affect
      cognition (such as benzodiazepines and anticholinergics). All medications will be recorded.
      The investigators expect most of the patients to be relatively chronic (mean illness
      chronicity approximately 15 years, based on previous studies), although we will not select
      for chronicity.

      All participants will provide written informed consent after receiving a full explanation of
      the procedures according to approvals by the Institutional Review Boards. They will arrive
      for three visits. In the first visit, they will be consented, complete the diagnostic
      interview, the rating scales, and will undergo one of three randomly assigned stimulation
      conditions: 1) anodal tDCS, 2) cathodaltDCS, and 3) sham stimulation. They will also undergo
      an electroencephalography (EEG) procedure, in order to more directly assess the effect of
      tDCS on brain function. This visit will take approximately five hours to complete, and breaks
      will be given as needed. Immediately following stimulation, participants will complete
      neurocognitive, social cognitive, and EEG measures. There will be two 20-minute stimulation
      sessions, with a break of one hour between the sessions. After each session, participants
      will be asked to complete a portion of the basic cognitive, social cognitive, and EEG
      measures, so that half of the measures will be completed after the first 20 minute
      stimulation session and the other half will be completed after the second 20 minute
      stimulation session. The order of administration of the neurocognitive, social cognitive, and
      EEG measures will be randomized across participants within each group. During the second and
      third visits, participants will undergo the remaining two stimulation conditions, one
      randomly assigned condition each visit. These visits will take approximately four hours to
      complete, and each visit will be separated by at least one week from the previous visit.
    

Intervention name(s): tDCS
Intervention type(s): Device
Intervention description(s): comparing anodal, cathodal, and sham tDCS
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment