Accelerated High-Dose tDCS for Depression

Inclusion Criteria: * Ages 18-70. * Current MDD diagnosis (MINI v7). * Baseline PHQ-9 \> 9. * Capacity to consent * Fluent English. Exclusion Criteria: * Bipolar or psychotic disorder * Primary anxiety disorders without concomitant major depression as defined above * Current significant suicidal ideation or behaviors require a higher level of care. * Use of neuromodulation therapies (e.g., ECT, TMS, VNS) within the past 6 months. * History of seizures, implanted cranial/ cardiac metal, or neurosurgery. * Use of medications that significantly reduce seizure threshold * Frequent/severe HA * Personal history of head trauma, concussion, or TBI * Catatonic or otherwise unable to perform the consent process * Current alcohol or substance-use disorder (moderate-severe). * Any non-uniformities in the skin under the electrode site, including eczema, severe rashes, hyperhidrosis, communicable skin disorders, sensitive skin (ex. eczema, severe rashes), blisters, open wounds, burns including sunburns, cuts or irritation (e.g. due to shaving), or other skin defects or lesions, as determined by clinical personnel * Pregnancy (urine test required for women of childbearing potential).