Night light increases the risk of depression by 30%
Excess light at night increases the risk of developing various mental illnesses, but it can also serve as a "cure" during the day.Researchers from Monash University conducted the world's largest study of the effect of day and night light on the risk of developing mental illness. The analysis showed that exposure to light at night disrupts the internal biological clock, increasing the risk of developing depression and other mental disorders, while exposure to daylight reduces this risk.
The study was conducted on data from 86,772 adults from the British Biobank. Participants were studied for their exposure to light, sleep, physical activity and mental health.
Researchers found that those exposed to a lot of light at night had a 30% increased risk of developing a major depressive episode. At the same time, those exposed to a lot of light during the daytime had a 20% reduced risk of depression.
A similar relationship was observed for the risk of self-harming behavior, psychosis, bipolar disorder, generalized anxiety disorder, and post-traumatic stress disorder. Results were confirmed when demographic factors, physical activity, sleep, shift work, living conditions, and cardiometabolic health were taken into account.
Artificial light and light from gadgets have disrupted our internal biological clock, the researchers add. But the simple practice of avoiding lighting at night and seeking brighter light during the day may be an effective non-pharmacological means of reducing the risk of serious mental health problems.