Investigating the effect of non-invasive transcranial current stimulation on auditory hallucinations in patients with schizophrenia. Normal neuronal activity is perturbed in schizophrenia, so selective targeting of this abnormal activity could serve as a treatment for schizophrenia and alleviate symptoms caused by abnormal neuronal activity, such as auditory hallucinations.

AIM 1: To evaluate the effect of transcranial direct current stimulation (tDCS) (2mA for 20min on five consecutive days) on auditory hallucinations in schizophrenia patients using the change in ratings on the Auditory Hallucination Rating Scale (AHRS) by patients before and after stimulation. We hypothesize that tDCS will modulate the abnormal neuronal activity found in schizophrenic patients and thereby decrease their auditory hallucinations when measured after stimulation.

AIM 2: To evaluate the long term effects of tDCS by having patients give a rating on the AHRS after one month has passed since stimulation and comparing this value to their baseline score and their score immediately after stimulation. We hypothesize that there will remain a significant reduction in auditory hallucination score in participants who received tDCS at one month.

Inclusion Criteria:

• Diagnostic and Statistical Manual IV (DSM-IV) diagnosis of schizophrenia, any subtype, or schizoaffective disorder, with refractory auditory hallucinations. Duration of illness >1 year.
• 18-99 years old.
• Clinically stable for at least 12 weeks, i.e. not requiring hospitalization or a change in level of care .
• On current antipsychotic doses for approximately 4 weeks or more.
• Capacity to understand all relevant risks and potential benefits of the study (informed consent) OR has a legal guardian who can complete consent forms on the patients behalf
• Right handed

Exclusion Criteria:

• Subjects with a DSM-IV diagnosis of alcohol or substance abuse (other than nicotine) within the last month or a DSM-IV diagnosis of alcohol or substance dependence (other than nicotine) within the last 6 months.
• History of significant head injury/trauma, as defined by loss of consciousness for more than 1 hour, or recurring seizures, or requiring later cognitive rehabilitation or causing cognitive sequelae.
• Prior brain surgery.
• Any brain devices/implants, including cochlear implants and aneurysm clips.
• Co-morbid neurological condition (i.e. seizure disorder, brain tumor).
• Medical or neurological illness (unstable cardiac disease AIDS, malignancy, liver or renal impairment) or treatment for a medical disorder that could interfere with study participation.
• Non English speakers.
• Pregnancy, nursing, or if female and fertile, unwilling to use appropriate birth control measures during study participation

Based on our randomized block design model, a block size of 10 (subjects, 20 total), 2 levels of (within-factors) TREATMENT and TIME each and a residual standard deviation of 14 (Brunelin et al., 2012), the power of our study is estimated to be 0.85 at the significant level alpha=0.05 and the difference of percentage change in 5 days of 15.

Adverse event data collected from the beginning of the study (4/2014) through the completion of the study (10/2014) for a total of 6 months.