If a participant qualifies for the study, we assign the participant by chance to receive either active transcranial light therapy or sham transcranial light therapy treatment. During sham transcranial light therapy visits, the transcranial light therapy device will not produce near infrared waves (e.g., light energy that cannot penetrate the skin and cranium). Participants have an equal chance of being assigned to the active transcranial light therapy or the sham transcranial light therapy when first randomized. Neither the participant, nor the clinician, nor any research staff will know which study group the participant belongs.