Transcranial Direct Current Stimulation (tDCS) as a Treatment for Cognitive Deficits in Schizophrenic

Schizophrenia patients (SZ) show profound and persistent cognitive deficits in attention, executive processing, and verbal and visuospatial memory, which persist even after psychotic symptoms are ameliorated. Cognitive deficits may be more important in preventing functional, occupational, and social recovery in SZ than other symptom domains and are not effectively treated by current pharmacological approaches. Transcranial direct-current stimulation (tDCS) is less expensive than other modalities (e.g. repetitive transcranial magnetic stimulation; rTMS), easily available, and has a good safety profile in healthy controls (HC) and SZ. However, these prior studies did not make use of a validated measure such as the MATRICS consensus battery (MCCB), which is now established as the standard for assessing cognitive improvement in SZ. Despite these promising preliminary results, this effect of tDCS in SZ needs to be confirmed and the underlying biological mechanism elucidated. Therefore, the investigators employed MCCB to evaluate the effects on improving cognition and functional MRI to explore the underlying mechanism.

Half of the participants will be randomized to tDCS group, while the other half will be randomized to receive sham tDCS. Active vs. sham treatment will be randomly using computer generated lists. Subjects and researcher-administrators of tDCS and testers or evaluators will be blind to treatment.The main cognitive outcome measure, the MCCB, will be administered at baseline and 1 day after the last tDCS session.Participants will be scanned once prior to tDCS sessions, and within one day after the 10th tDCS sessions using our Siemens 3T Verio MRI scanner.

Inclusion criteria

• Subjects who have cognitive deficits as indicated by a score of < 85 on RBANS, and meet criteria for DSM-5 diagnosis of chronic SZ, schizoaffective disorder (SA), or schizophreniform disorder (SZF), and who are stably treated with antipsychotic medications and are not in acute exacerbation of illness symptoms.

Exclusion criteria

• Patients with risk factors for an MRI scan, seizure disorder, and for women of childbearing age who are pregnant or regularly engaging in sexual activity and not regularly using an acceptable birth control method (systemic or double-barrier).