tDCStDCS for Late-Life Depression

Inclusion Criteria:

Participants must meet all of the following criteria:

1. age 60 years or older;
2. diagnosis of unipolar major depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), confirmed by the Structured Clinical Interview for DSM-5 (SCID-5);
3. score of 16 or higher on the Quick Inventory of Depressive Symptomology-Clinician Rated (QIDS-C) at screening;
4. stable antidepressant regimen for at least four weeks prior to enrollment, if applicable;
5. willingness and capacity to provide informed consent;
6. Clinical Dementia Rating scale of 0 or 0.5.
7. availability of an informant who has sufficient knowledge of the participant's daily functioning as ascertained by the study team.

Exclusion Criteria:

Participants meeting any of the following criteria will be excluded:

1. contraindications to tDCS including metallic cranial implants, skin conditions at electrode sites (eczema, open wounds, burns, lesions), or history of adverse reaction to tDCS;
2. contraindications to magnetic resonance imaging (MRI) including pacemaker, cochlear implants, ferromagnetic implants, or claustrophobia;
3. depressive disorder due to a medical condition;
4. psychotic depression;
5. history of seizures or epilepsy;
6. bipolar disorder;
7. psychotic disorders;
8. severe personality disorder;
9. active substance use disorder within the past six months or history of substance induced mood or psychotic disorder;
10. neuromodulation treatment including electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), tDCS, or vagus nerve stimulation (VNS) within the past six months;
11. active suicidal ideation with plan or intent requiring a higher level of care;
12. concurrent use of medications that substantially lower seizure threshold;
13. pregnancy;
14. a clinically established diagnosis of dementia as reported in the participant's health record or scoring 1 or above on CDR;
15. medically unstable in the clinical opinion of the principal investigators.