Participants are randomized a second time after 6-weeks in the study. If the participant were in the sham group the first 6-weeks, that participant may receive the active transcranial light therapy treatment after re-randomization. If the participant were already in the active transcranial light therapy group during the first 6-weeks the participant continues receiving the active treatment. All in all, participants have a 1 in 3 chance of receiving the active transcranial light therapy treatment at some point during the study.