Near Infrared Spectroscopy (NIRS) for Assessment of Depression

Develop a NIRSIT testing protocol that can be administered in the diagnostic setting and reliably distinguishes the symptoms and severity of depression, with the help of repeated measure (up to five visits per subject) comparison of patients being treated for Major Depressive Disorder with control, non-depressed subjects.

Inclusion Criteria: * All subjects who sign informed consent. * Controls: Volunteers over 18 years of age who are not depressed. * Patients over 18 years of age with a diagnosis of Major Depressive Disorder, receiving clinical therapy at SFVAMC. Exclusion Criteria: * Subjects who cannot sign informed consent. * Exclusion criteria for control subjects: 1.Depression 2.Anxiety, psychotic, substance abuse, mood and personality disorders 3.Major neurocognitive disorders such as Alzheimer's disease and other dementias 4.Neurologic disorders with anatomic lesions including traumatic brain injury, stroke, tumor and arteriovenous malformation * Exclusion criteria for depressed patients: 1.Psychotic disorders like schizophrenia 2.Major neurocognitive disorders such as Alzheimer's disease and other dementias 3.Neurologic disorders with anatomic lesions including traumatic brain injury, stroke, tumor and arteriovenous malformation 4.Not receiving clinical therapy for depression at SFVAMC'