Transcranial Alternating Current Stimulation for Major Depressive Disorder

Investigating the effects of non-invasive transcranial alternating current stimulation (tACS) on patients with Major Depressive Disorder (MDD).

Central Hypothesis: Non-invasive brain stimulation that suppresses alpha oscillation reduces cortical hyperactivity and causes a clinical improvement

Aim 1: To conduct a pilot clinical trial to establish feasibility and to collect first effectiveness data for the use of tACS to renormalize pathological alpha oscillations in the dorsolateral prefrontal cortex (dl-pfc) of unmedicated patients with MDD by comparing MADRS scores from baseline and one month follow up.

Aim 2: Compare alpha oscillation power from resting state EEG recordings on the first and last day of stimulation. Collect EEG data at the one month follow up visit using this data to analyze alpha frequency activity as a pilot study for derivation of EEG biomarkers.

Eligibility Criteria:
Inclusion Criteria:

* Male or female, 18-65 years old
* Diagnostic and Statistical Manual of Mental Disorder, 4th edition (DSM-IV) diagnosis of MDD; unipolar, non-psychotic
* Hamilton Depression Rating Scale score \>8
* Capacity to understand all relevant risks and potential benefits of the study (informed consent)
* Meet criteria for low suicide risk
* Willing to comply with all study procedures and be available to do so for the duration of the study
* Women of reproductive potential must use highly effective contraception

Exclusion Criteria:

* DSM-IV diagnosis of alcohol of 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
* Current use of benzodiazepines or anti-epileptic drugs
* Current axis I mood, or psychotic disorder other than major depressive disorder
* Lifetime comorbid psychiatric bipolar or psychotic disorder
* Eating disorder (current or within the past 6 months)
* Obsessive-compulsive disorder (lifetime)
* Post traumatic stress disorder (PTSD; current or within the last 6 months)
* Attention Deficit Hyperactivity Disorder (ADHD; currently under treatment)
* Anything that, in the opinion of the investigator, would place the participant at increased risk or preclude the participant's full compliance with or completion of the study
* Neurological disorders, including but not limited to history of seizures (except childhood febrile seizures and ECT induced seizures), dementia, history of stroke, Parkinson's disease, multiple sclerosis, cerebral aneurism
* 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, reoccurring seizures or 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)
* Non English speakers
* Pregnancy, nursing, or if female and fertile, unwilling to use appropriate birth control measures during study participation