Targeting Auditory Hallucinations With Alternating Current Stimulation

The investigator's primary objective is to provide further evidence for the effectiveness of
transcranial alternating current stimulation (tACS) to treat auditory hallucinations and to
collect preliminary data on whether maintenance stimulation sessions can prolong the duration
of stimulation-induced clinical benefits. The investigators will be looking into effects of
tACS to re-normalize pathological alpha oscillations in the dorso-lateral prefrontal cortex
(dl-PFC) of patients with schizophrenia or schizo-affective disorder by comparing Auditory
Hallucination Rating Scale (AHRS) scores immediately before the first stimulation session,
immediately after the last stimulation session, and at the end of the 8 weeks of maintenance
sessions. As a secondary objective, the investigators will assess the differential clinical
effects of active sham and 10Hz tACS on electroencephalogram (EEG) measures of alpha
oscillations. The investigators will also be using source localization techniques in EEG
analysis, based on individual locations of the scalp electrodes and anatomical structures
with the use of structural magnetic resonance imaging (sMRI).

Inclusion Criteria:

- DSM-IV diagnosis of schizophrenia, any subtype, or schizoaffective disorder with
refractory hallucinations. Duration of illness >1 year

- 18 - 70 years old

- Clinical stable for at least 12 weeks i.e. not requiring any hospitalization or a
change in level of care

- On current antipsychotic doses for at least 4 weeks

- Experience at least 3 auditory hallucinations per week

- Stable auditory hallucinations as demonstrated by having less than or equal to 20%
change in AHRS scores across a 2 week interval during the screening period

- Capacity to understand all relevant risks and potential benefits of the study and to
provide written informed consent, OR has a legal guardian who can provide the informed
consent on the patient's behalf with the patient providing written assent to
participate

Exclusion Criteria:

- 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

- Positive urine test of cannabis, cocaine, amphetamine, barbiturates, opiates

- Current treatment (within 4 weeks) with psychotropic agents including benzodiazepines
that are taken on a daily basis (limit prn use to greater than 48 hours before
participating in a study session) or any of the following medications: carbamazepine,
gabapentin, lamotrigine, and valproic acid

- 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

- history of traumatic brain injury that required subsequent cognitive rehabilitation,
or caused cognitive sequelae

- A difference of greater than 20% in AHRS scores between screening visits

- Prior brain surgery

- Any brain devices/implants, including cochlear implants and aneurysm clips

- Co-morbid neurological condition (e.g. seizure disorder, brain tumor)

- Non English speakers

- Female participants who are pregnant, nursing, or unwilling to use appropriate birth
control measures during study participation

- Anything that, in the opinion of the investigator, would place the participant at
increased risk or preclude the participants' full compliance with or completion of the
study