A large cross-sectional study of 86,772 UK adults found clear links between light exposure patterns and mental health outcomes. Higher night-time light exposure was associated with increased risk of major depressive disorder, generalized anxiety disorder, PTSD, psychosis, bipolar disorder, and self-harm. Conversely, higher day-time light exposure was linked to reduced odds of major depressive disorder, PTSD, psychosis, and self-harm—even after adjusting for sleep, activity, and demographic factors. The authors suggest that avoiding light exposure at night and seeking it during the day may serve as a simple, effective, non-pharmacological strategy to support mental well-being.

Reference — Burns, A. C., Windred, D. P., Rutter, M. K., Olivier, P., Vetter, C., Saxena, R., Lane, J. M., Phillips, A. J. K., & Cain, S. W. (2022). Low daytime light and bright night-time light are associated with psychiatric disorders: An objective light study in >85,000 UK Biobank participants [Preprint]. medRxiv. https://doi.org/10.1101/2022.10.16.22280934

Keywords & Nodes

• light / dark
• sleep
• energy
• Visual perception and time perception are intertwined.
• 6. Biology
• Mental health is metabolic health.