The research for this study was done out of Australia and is the largest study on light exposure and mental health to date, with nearly 87,000 participants. The data used was collected from the UK Biobank, with the researchers looking at things like light exposure, sleep, physical activity, and mental health.
Based on the findings, lighting could play more of a role in mental health than we thought, with participants who had increased light exposure at night showing an increased risk of psychiatric disorders like anxiety and depression. Namely, light at night increased risk of depression by 30%, and similar patterns were also seen for self-harm, psychosis, bipolar disorder, anxiety, and PTSD.
And as the study’s lead author, Sean Cain Ph.D., notes in a news release, these findings were consistent even after accounting for compounding variables like shiftwork, cardio-metabolic health, and urban versus rural living.
The good news is, the study also found that light exposure during the day can serve as a protective measure for mental health and reducing psychosis risk.