the effect of transcranial direct current stimulation on human brains: a neuroimaging study

Conditions: Chronic Schizophrenia

Summary: the purpose of this project is to examine brain function before, during, and after the administration of tdcs (transcranial direct current stimulation). the brain can perform its job well or poorly depending on many things. the investigators will be using computer tasks and paper and pencil questionnaires to measure the relationship between brain performance and the administration of tdcs. in addition, the study team will be using functional magnetic resonance imaging (fmri) and related imaging techniques to see how your brain works and compare it with the results we collected from the paper and pencil questionnaires. this study will enroll both schizophrenia patients as well as healthy volunteers without any major psychiatric disorder or physical illness.

this is a placebo condition controlled double blind randomized prospective study where the study team plan to acquire clinical, neurocognitive and imaging data in schizophrenia patients and healthy controls. those who are eligible for the study will be consented, and will be randomized into either group a or b. the length of the study is four weeks. subjects in both groups will undergo the same procedure, except that while subjects from group a unbeknownst to them will receive only a sham stimulation of tdcs (placebo condition), the subjects from group b will receive real tdcs stimulation. real tdcs stimulation will involve ten 20 minute stimulations daily (at 2 ma anode over the left dlpfc while cathode over the right suborbital region) on 5 weekdays of two consecutive weeks, while sham will contain 20 minute sessions as well, but only the first minute will be with 2ma, then unbeknownst to the subject, the unblinded research assistant will turn off the stimulation. the subjects will be told that they can be given either a sham or real stimulation and will be asked at the end of the experiment to fill out a visual analog scale indicating their guess about being in the real or sham arm. following the first two weeks of the study, there will be a follow up period of two weeks when no stimulation or sham will be administered. subjects, raters, clinicians and most of the research persons will all be kept blind in regards to their placebo or stimulation status until the end of the study. research persons analyzing neuroimgaing data will break blindness after subject leaves the study, to continuously monitor neuroimaging findings.

Eligibility criteria:
inclusion criteria: 1. between 18 and 60 years of age 2. subject is competent to provide informed consent additional inclusion criteria for schizophrenia group: 3. pt diagnosed with schizophrenia according to dsm v criteria. exclusion criteria: 1. mri contraindications 2. person with any kind of neurostimulator or pacemaker, or built in electrical device even if it is mri safe 3. skin lesions at the site of electrodes and any documented head or neck dermatological disorder 4. pregnancy 5. any major neurological (seizures, sclerosis multiplex, etc) disorder 6. individuals who are illiterate and/or visually impaired 7. subjects with history of mental retardation, learning disorders or traumatic brain injury additional exclusion criteria for healthy group: 8. past or current history of any psychotic illness in the subject or in first degree family members 9. self report of illicit drug use (except marijuana) in the past. use of marijuana during the last 3 month. 10. any use of any psychotropic medications (antipsychotics, ssri, mood stabilizers, benzodiazepines, stimulants) in the last month.