Research suggests that our bodies are adapted to sleep during darkness and become active during daylight. Disruptions in circadian rhythms may increase the risk of metabolic diseases and some types of cancer. Now, a study in mice has found that being exposed to light at night for prolonged periods may contribute to depression.
Researchers at Ohio State University found that mice housed in a lighted room 24 hours a day exhibited more symptoms of depression than did mice that had a normal light-dark cycle. When mice that lived in constant light had the option to escape into an opaque tube, they showed fewer symptoms of depression than mice who did not have an escape from 24-hour light. The depression tests in mice involved such things as measuring how much sugar water they drank.
The study contributes to the growing body of research that circadian rhythms are highly influential in health.
The study was presented this week at the annual meeting of the Society for Neuroscience in Chicago. It will be published in December in the journal Behavioural Brain Research.