Bright light exposure augments cognitive behavioral therapy for panic and posttraumatic stress disorders: a pilot randomized control trial

Bright light (BL) therapy is clinically utilized for treatment of sleep–wake disorders through the manipulation of circadian oscillation. It is also extended to depressive disorders including seasonal affective disorder through emotional regulation. Recently, it has been suggested that BL facilitates memory encoding and consolidation via another psychophysiological mechanism of perceptual information processing in the brain. In particular, BL can help to alleviate stress associated with processing of fear memories. In this study, we explored a potential application of BL for treatment of stress-induced and fear circuitry disorders in patients receiving exposure-based cognitive behavioral therapy (CBT). Fourteen patients with panic disorder (PD) or posttraumatic stress disorder (PTSD) were enrolled in a single-blind, randomized control trial to assess BL exposure (8000-lux, 30 min, 9 times, 2 weeks apart) compared to sham light (SL) exposure (800-lux, the same duration and frequency), while patients were concurrently receiving exposure-based CBT. The State Trait Anxiety Index (STAI) and the self-rating version of Montgomery–Asberg Depression Rating Scale (MADRS-S) assessed anxiety-related severity scores before and after therapy. After dropouts, 10 participants remained. STAI and MADRS-S scores showed a significantly greater reduction in the BL group than in the SL group. BL may be an effective augmentative therapy when used with exposure-based CBT for PD and PTSD patients. Future trials with larger sample sizes that are adequately statistically powered are required to confirm these preliminary findings.