The purpose of the current study is to perform a unified, homogeneous data collection protocol that includes a large cohort of patients undergoing different treatment options for Major Depressive Disorder (MDD) as an avenue for investigating optimal biomarkers for depression treatments on an individual patient level.

Inclusion Criteria:

Ketamine cohort

• Adult between the ages of 18 - 65, inclusive at time of enrollment
• Primary diagnosis of MDD as defined by DSM-5
• Determined by clinic to be eligible for ketamine treatment and agrees to receive ketamine treatment
• Agrees to start ketamine treatment in conjunction with study participation to capture pre-treatment measurements accurately
• Has not received a ketamine treatment course in the past 12 months
• Has not received a TMS treatment course in the past 3 months
• Ability to consent for themselves
• Fluency in English (speaking and reading)

SPRAVATO cohort

• Adult between the ages of 18 - 75, inclusive at time of enrollment
• Primary diagnosis of MDD as defined by DSM-5
• Determined by clinic to be eligible for SPRAVATO treatment and agrees to receive SPRAVATO treatment
• Agrees to start SPRAVATO treatment in conjunction with study participation to capture pre-treatment measurements accurately
• Has not received a ketamine or SPRAVATO treatment course in the past 12 months
• Has not received a TMS treatment course in the past 3 months
• Ability to consent for themselves
• Fluency in English (speaking and reading)

TMS cohort

• Adult between the ages of 18 - 65, inclusive at time of enrollment
• Primary diagnosis of MDD as defined by DSM-5
• Determined by clinic to be eligible for TMS treatment and agrees to receive TMS treatment
• Agrees to start TMS treatment in conjunction with study participation to capture pre-treatment measurements accurately
• Has not received a TMS treatment course in the past 12 months
• Has not received a ketamine or SPRAVATO treatment course within the last 3 months
• Ability to consent for themselves
• Fluency in English (speaking and reading)

Antidepressants cohort

• Adult between the ages of 18 - 65, inclusive at time of enrollment
• Primary diagnosis of MDD as defined by DSM-5
• Determined by clinic to be eligible for antidepressant treatment and agrees to receive antidepressant treatment
• Agrees to start antidepressant treatment in conjunction with study participation to capture pre-treatment measurements accurately
• Has not taken antidepressants in the past 3 months
• Has not received a TMS, SPRAVATO, or ketamine treatment course in the past 3 months
• Ability to consent for themselves
• Fluency in English (speaking and reading)

Exclusion Criteria:

• Is or may be pregnant (for participant of childbearing potential [POCBP]), even if they have been cleared to receive the depression treatment

• Unable or unwilling to wear the TD-fNIRS headset

• Has had ECT in the past 3 months

• Major visual or auditory deficits that would prevent study task completion

• Hospitalizations and/or unstable health/medical condition/treatment in the last 30 days

• Major medical illnesses and psychiatric conditions including:

  • Alzheimer's/Mild Cognitive Impairment
  • Parkinson's disease
  • Motor neuron diseases
  • Multiple Sclerosis
  • Brain Tumor
  • Stroke
  • Encephalitis
  • Meningitis
  • Epilepsy
  • TBI with serious results (coma, unconscious for >2 hrs, or skull fracture)
  • Current serious psychiatric conditions (bipolar disorder, schizophrenia, or psychosis)

• Any other clinically significant medical condition or circumstance that, in the opinion of the Investigator, could affect patient safety, preclude evaluation of response, interfere with the ability to comply with study procedures, or prohibit completion of the study

• Not an appropriate candidate for the study in the judgment of the investigator(s)

Adult participants seeking treatment for depression at a participating clinic/study site. Separate cohorts of participants will be enrolled depending on the treatment they have been prescribed. No clinical decisions will be made based on the data acquired for this study, and participation in the study has no influence on treatment decisions.