0884 Morning Blue Light Exposure Improves Sleep and Fear Extinction Recall in PTSD

Abstract

Abstract Introduction Sleep disruption is considered to be the “hallmark symptom” of post-traumatic stress disorder (PTSD). In addition to sleep deficits, patients with PTSD who undergo experimental fear conditioning also typically show a deficit in the ability to recall extinction memories relative to those without the disorder. As memory consolidation is strongly influenced by sleep, we hypothesized that an intervention that regulates sleep and circadian rhythms (i.e., morning exposure to blue-wavelength light) might enhance consolidation and retention of learned extinction memory during a fear conditioning/extinction protocol among patients with PTSD. Methods Thirty-eight individuals with PTSD (18 male; Age=30.8, SD=9.0) underwent a well-validated fear conditioning and extinction protocol and were then randomly assigned to receive either BLUE (469 nm; n=20) or placebo AMBER (578 nm; n=18) morning light therapy for 30-minutes daily for 6-weeks. Participants returned after 6 weeks to undergo post-treatment extinction recall when exposed to the same previously conditioned stimuli. Extinction recall magnitude (ERM) at follow-up was calculated as the difference in skin conductance response (SCR) between the “extinguished” and the “never-extinguished” stimuli. Results BLUE light was associated with an increase in sleep duration relative to AMBER (p=.016). Based on the ERM, participants in the BLUE group showed sustained retention of extinction memory, while those in the placebo AMBER group showed a resurgence of the fear response after 6-weeks (p=.016). Moreover, retention of ERM was correlated with improvement in sleep on the Insomnia Severity Index for the BLUE (r=.44, p