The objective is to determine the effectiveness of daily morning blue light therapy (BLT) for regulating the circadian rhythm to improve mood and reduce suicidal thinking. Our working hypotheses are that daily exposure to morning blue light for two weeks will 1) lead to a phase advance entrainment of sleep timing relative to a placebo light therapy, 2) lead to improved/sustained mental health outcomes, including suicidal ideation, relative to a placebo light therapy, and that 3) most military Service members will rate the use of a light headset device acceptable as a treatment option after their experience.~Over a 3-year period of performance, we aim to 1) determine the effectiveness of daily morning BLT for regulating circadian timing and sleep, 2) determine the effectiveness of daily morning BLT for sustaining or improving mental health outcomes, including suicidal ideation, relative to placebo light therapy, and 3) determine the acceptability and buy-in from military personnel using a daily light headset device.~During this study, 400 military personnel will complete a double-blind, placebo-controlled, counterbalanced, crossover design study of the effects of 30-minutes of daily morning blue light therapy (BLT) versus amber placebo light therapy (PLT) on measured sleep and mental health outcomes. Participants will complete two weeks of morning BLT with a commercially available headset with four built-in light-emitting diode (LEDs) and internal compliance monitors, and two weeks wearing the same type of glasses fit with amber placebo light-emitting diode (LEDs), in a counterbalanced order, separated by a four-week washout period. An online assessment battery for mental health and suicidal ideation will be completed before and after each treatment period, and sleep/circadian rhythms will be monitored throughout via 5-channel at-home EEG recordings, continuous actigraphy and daily brief sleep/mood/suicidal ideation logs.
Mood dysregulation and suicidal ideation are closely associated with disruption of sleep and circadian rhythms. Moreover, sleep problems and circadian disruption are commonplace features of military life. Critically, specifically timed light exposure plays a powerful role in regulating mood, circadian rhythms, and sleep-wake patterns. Therefore, we propose to conduct a large-scale clinical trial on the effectiveness of morning light exposure treatment for improving sleep-wake patterns, emotional and mental health, and suicidal thoughts in military personnel.