tDCS for Late-Life Depression

Inclusion criteria

Participants must meet all of the following criteria:

• age 60 years or older;
• diagnosis of unipolar major depressive disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), confirmed by the Mini International Neuropsychiatric Interview (MINI);
• score of 17 or higher on the 17-item Hamilton Depression Rating Scale (HDRS-17) at screening;
• stable antidepressant regimen for at least four weeks prior to enrollment, if applicable;
• capacity to provide informed consent;
• Clinical Dementia Rating scale of 0 or 0.5.

Exclusion criteria

Participants meeting any of the following criteria will be excluded:

• contraindications to tDCS including metallic cranial implants, skin conditions at electrode sites (eczema, open wounds, burns, lesions), or history of adverse reaction to tDCS;
• contraindications to magnetic resonance imaging (MRI) including pacemaker, cochlear implants, ferromagnetic implants, or claustrophobia;
• history of seizures or epilepsy;
• bipolar disorder, psychotic disorders, or severe personality disorder;
• dementia or MoCA score below 17;
• substance use disorder within the past six months;
• neuromodulation treatment including electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS), tDCS, or vagus nerve stimulation (VNS) within the past six months;
• active suicidal ideation with plan or intent requiring a higher level of care;
• concurrent use of medications that substantially lower seizure threshold;
• pregnancy.