Transcranial Laser Therapy, Continuous and Pulsed Light, for Major Depressive Disorder (ELATED-3)

Inclusion Criteria: * Participant age at screening will be between (\>=)18 and 70 years old (inclusive). * Participant meets the criteria for major depressive disorder * Participants informed consent obtained in writing * Participant is available to participate in the study for at least 12 weeks Exclusion Criteria: * Significant skin conditions near the application site * Any use of light-activated drugs (photodynamic therapy) within 14 days prior to study enrollment * Recent history of stroke * The participant failed more than 2 adequate treatment with Federal Drug Administration approved antidepressants during current episode per antidepressant treatment response questionnaire criteria (less than 50% decrease in depressive symptomatology). * Structured psychotherapy focused on treating the subject's depression (i.e. cognitive behavioral therapy or interpersonal therapy) is permitted if started at least 8 weeks prior to the screening visit. * Substance dependence or abuse in the past 3 months. * History of a psychotic disorder or psychotic episode (current psychotic episode per M.I.N.I neuro-psychiatric assessment). * Bipolar affective disorder (per M.I.N.I neuro-psychiatric assessment). * Unstable medical illness, defined as any medical illness which is not well-controlled with standard-of-care medications (e.g., insulin for diabetes mellitus, hydrochlorothiazide for hypertension). * Active suicidal or homicidal ideation (both intention and plan are present), as determined by Columbia Suicide Severity Rating Scale * Cognitive impairment (Montreal Cognitive Assessment \<21) * The participant has a significant skin condition (i.e., hemangioma, scleroderma, psoriasis, rash, open wound or tattoo) on the subject's scalp that is found to be in proximity to any of the procedure sites. * The subject has an implant of any kind in the head (e.g. stent, clipped aneurysm, embolised arteriovenous malformation, implantable shunt - Hakim valve). * Any use of light-activated drugs (photodynamic therapy) within 14 days prior to study enrollment (in US: Visudyne (verteporfin) - for age related macular degeneration; Aminolevulinic Acid- for actinic keratoses; Photofrin (porfimer sodium) - for esophageal cancer, non-small cell lung cancer; Levulan Kerastick (aminolevulinic acid hydrogen chloride) - for actinic keratosis; 5-aminolevulinic acid for non-melanoma skin cancer) * Women of child-bearing potential must use a double-barrier method for birth control (e.g. condoms plus spermicide) if sexually active.