Blue Light Therapy Improves Severity of PTSD-Related Symptoms and Sleep Disturbance

by | Dec 22, 2022 | 2022, Alternative Therapies, Brain Health, Cognitive Health, Sleep, Stress

Written by Taylor Woosley, Staff Writer. 6-week treatment of blue light exposure for 30-minutes each morning resulted in significant improvements in the severity of PTSD symptoms, particularly regarding sleep quality and dysfunction. 

depressed young manPost-traumatic stress disorder (PTSD) is a highly disabling anxiety disorder characterized by fear, stress, and negative alterations in mood1. PTSD has a prevalence of approximately 6-8% in the general population, although this can increase to 25% among groups who have experienced severe psychological trauma2. It is a syndrome that serves as a psychiatric disorder that results from the intersection of nature and nurture, or gene and environment3. PTSD is associated with structural, metabolic, and molecular changes in several brain regions including the amygdala, hippocampus, and prefrontal cortex, which play an essential role in memory function4.

Short-wavelength light exposure (~480nm, blue light) plays multiple important roles in biopsychological functioning5. Light therapy has physiological effects by resynchronizing the circadian system, enhancing alertness, and acting on serotonin, and other monoaminergic pathways6. There is also evidence that blue light may promote affective arousal and modulate emotional brain responses7.

Vanuk et al. conducted a randomized, double-blind, placebo-controlled trial to assess whether blue light treatment would improve sleep quality, decrease severity of PTSD symptoms, and sustain fear extinction learning relative to amber placebo light. Study inclusion consisted of having a diagnosis of PTSD based on the Structured Clinical Interview for DSM-V, who were currently experiencing symptoms, and were between the ages of 18 and 50 years old. 90 subjects were initially enrolled and 82 completed the study. Participants were divided into either the blue light treatment group (BLT) (n=43) or the amber light treatment group (ALT) (n=39). Over the course of 7 weeks, subjects completed three laboratory visits, including two full-day neurocognitive assessments and neuroimaging scans, along with completing a 6-week at-home light treatment regimen for 30-min each morning.

At the first visit, participants were evaluated to assess their PTSD severity, along with other psychopathology. Additionally, they were informed to complete a daily sleep diary to evaluate sleep quality and activity. During visit two subjects completed a baseline neurocognitive and neuroimaging assessment. Afterwards, they engaged in the initial phase of a fear conditioning paradigm (Fear Conditioning, Extinction Learning, and Extinction Recall). Upon completion of the 6-week light treatment, participants completed further neurocognitive and neuroimaging assessments, with an additional Fear Extinction memory component of their MRI scan. Significant findings of the study are as follows:

  • Subjects showed a decrease in PTSD symptoms and severity between baseline and post-treatment. A strong effect of time on both PTSD severity was noted, beta = –0.62, 95% CI [–0.80, –0.44], t (154) = –6.67, p < 0.001, as assessed by the Clinician-Administered PTSD Scale (CAPS-5).
  • The effect of time was not qualified by a significant group x time interaction, ps > 0.290, suggesting that both the blue light and amber light group improved in PTSD symptoms and severity.
  • Participants in both light treatment groups reported improved sleep (indicating fewer symptoms of disrupted sleep), beta = –0.23, 95% CI [–0.37, –0.09], [t (151) = –3.21, p = 0.001] and higher FOSQ scores, beta = 0.07, 95% CI [0.00, 0.14], t (154) = 2.16, p = 0.031.

Significant findings of the study show that exposure to blue-wavelength light for 30-min each morning for 6-weeks improved PTSD symptoms and sleep quality. Additionally, subjects in the amber light group also experienced significant improvement in PTSD symptoms but not in subjective sleep outcomes. Further research should continue to explore the benefits of blue light therapy on psychiatric disorders. Study limitations include the small sample size of the study and the multiple confounds leading to many presented analyses being underpowered.

Source: Vanuk, John R., Edward F. Pace-Schott, Ayla Bullock, Simon Esbit, Natalie S. Dailey, and William DS Killgore. “Morning blue light treatment improves sleep complaints, symptom severity, and retention of fear extinction memory in post-traumatic stress disorder.” (2022).

© 2022 Vanuk, Pace-Schott, Bullock, Esbit, Dailey and Killgore. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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Posted December 22, 2022.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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