POTENTIAL AGE MODERATION OF BLUE LIGHT THERAPY ON PTSD SLEEP SYMPTOM SEVERITY

Abstract

One of the primary symptoms of PTSD is disruption of sleep. Effective treatment for sleep dysfunction in PTSD populations is lacking. There is a need for new therapeutic interventions because sleep is necessary for memory consolidation and emotion processing. Since sleep, memory, and mood are associated with one another, it is reasonably expected that if sleep in individuals with PTSD can be improved, enhanced memory and emotional processing will follow suit which may result in diminished or even disappearance of symptoms. A potential non-pharmacological approach for treating sleep problems is through morning blue light therapy (BLT). This thesis aimed to determine the effectiveness of BLT at treating PTSD symptoms, specifically through assessing subjective improvements in sleep quality and disturbances over six weeks, as measured by the Pittsburg Sleep Quality Index (PSQI). In addition, the impact of age on the effectiveness of light treatment was examined to see if changes in the eye physiology that arise from aging, specifically cataracts, negatively affect the capability for light to stimulate intrinsically photosensitive retinal ganglion cells (ipRGCs). It was hypothesized that daily administration of morning BLT would positively influence sleep quality more than the placebo condition of amber light therapy (ALT), but the extent of improvements in sleep would be moderated by older age. The results showed that sleep quality improved after six weeks of light treatment, regardless of light condition and age. However, there were trends towards better sleep in the younger population. This suggests that both wavelengths of light were effective at improving sleep in the PTSD population, but younger individuals may gain more improvements from light treatment than older individuals. These findings may inform further studies that investigate BLT at treating psychological disorders.