The Epidemiology of Light and Mental Health in the UK Biobank

Modern electric lighting environments can disrupt the human circadian system by blurring the distinction between day and night. Many psychiatric disorders are characterised by disrupted circadian rhythms. In this thesis, we examined the association of free-living day and night light exposure with risk for and symptom severity of psychiatric illness. We also used genetics to identify the heritable basis of light sensitivity. We report that low daylight and bright night light exposure, as well as increased light sensitivity, are associated with risk for psychiatric illness, including: depression, PTSD, psychosis and bipolar disorder.