Light-Based brain scanner may unlock secrets of depression and memory loss

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria General Inclusion Criteria (across all diagnostic groups): * 18 years and older * Ability to provide written informed consent * Adequate cognitive and language abilities to understand and complete study tasks, including clinical assessments and fNIRS procedures * Confirmed clinical diagnosis of major depressive disorder, bipolar disorder, or mild cognitive impairment (MCI) * Stable psychiatric or cognitive condition, without acute episodes requiring immediate intervention Specific Inclusion Criteria (for diagnostic groups): * Healthy control o No past or current psychiatric or cognitive disorder * Major depressive disorder (MDD): * Diagnosis of major depressive disorder, confirmed through clinical evaluation. * No history of bipolar disorder or psychotic symptoms. * Bipolar disorder: o Diagnosis of bipolar disorder I or II, confirmed through clinical evaluation. * Mild Cognitive Impairment (MCI): * Pre-existing clinical diagnosis of mild cognitive impairment, supported by neuropsychological testing and/or MRI, PET scan data. * No history of major psychiatric disorders, such as major depression, bipolar disorder or schizophrenia. Exclusion Criteria General Exclusion Criteria (across all diagnostic groups): * Active primary psychotic or substance use disorders (except nicotine dependence) within the past year * Any severe or unstable medical condition that could interfere with participation or data collection * Any active neurological condition (including seizure disorder, traumatic brain injury, stroke) that could affect cognitive functioning or brain imaging results * Inability to comply with study procedures, including cognitive testing, fNIRS assessment, or other assessments required by the protocol * Pregnant women will be excluded due to potential physiological changes that could affect study outcomes Specific Exclusion Criteria (for diagnostic groups): * Healthy control o Any past or current psychiatric or cognitive disorder * Major depressive disorder (MDD): * Diagnosis of bipolar disorder or schizophrenia. * Brain stimulation therapy within the past 3 months. * Bipolar disorder: o Diagnosis of schizophrenia or schizoaffective disorder. * Mild Cognitive Impairment (MCI): * Diagnosis of dementia. * Significant cognitive impairment preventing understanding or completion of study tasks.