Even a hint of light past bedtime could lead to depression: Study

(Representational image)

New Delhi: Do you have a habit of sleeping with the lights or a night light on? If your answer is yes, then you may be risking depression, a study has warned.

As per the new research, any kind of light past bedtime, whether it's from a gap in the curtains, a flash from your smartphone or even a night light, could pave the way to depression as it could confuse your body clock.

Previous studies have associated nocturnal light exposure with a disruption in the body's sleep-wake cycle, but have struggled to explain how this impacts depression.

According to the Daily Mail, while the new study by researchers at Nara Medical University does not solve the mystery, it provides some of the clearest evidence to date that the link is stronger than most realize.

Researchers led by Dr Kenji Obayashi recruited 863 elderly adults, with the average age of 72 years, who did not have depressive symptoms – anxiety or a persistent feeling of sadness – at the start of the two-year study.

They measured light levels in their room by placing light meters at the heads of everyone's bed to determine the amount of light their subjects would see while going to sleep. About 710 participants slept in a completely dark room, while the rest of the subjects were exposed to light at night.

The participants were also asked to keep sleep diaries and completed surveys that monitored the development of depressive symptoms.

It was found that compared to the dark group, people exposed to more than 5 lumens of light at night had a significantly higher risk of developing depressive symptoms, the Daily Mail reported.

This isn't the first study to link nocturnal light exposure to the mood disorder.

Research published in a 2009 issue of Behavioral Brain Research found mice that were put in a room that was lit 24 hours a day had more depressive symptoms than those that had a normal light-dark cycle.