The Effect of Transcranial Direct Current Stimulation on Human Brains: A Neuroimaging Study

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.

Inclusion criteria

• Between 18 and 60 years of age
• Subject is competent to provide informed consent

Additional inclusion criteria for schizophrenia group:

• Pt diagnosed with schizophrenia according to DSM V criteria.

Exclusion criteria

• MRI contraindications
• Person with any kind of neurostimulator or pacemaker, or built in electrical device even if it is MRI safe
• Skin lesions at the site of electrodes and any documented head or neck dermatological disorder
• Pregnancy
• Any major neurological (seizures, sclerosis multiplex, etc) disorder
• Individuals who are illiterate and/or visually impaired
• Subjects with history of mental retardation, learning disorders or traumatic brain injury

Additional exclusion criteria for healthy group:

• Past or current history of any psychotic illness in the subject or in first degree family members
• Self report of illicit drug use (except marijuana) in the past. Use of marijuana during the last 3 month.
• Any use of any psychotropic medications (antipsychotics, SSRI, mood stabilizers, benzodiazepines, stimulants) in the last month.