We have become digital citizens and playing into this space is inevitable, says the writer. File photo

London - Exposure to light at night – even from a laptop computer or tablet – may cause depression, scientists say.

Researchers found that bright light in the early hours, such as that found in a living room or in the workplace at night for shift workers, can elevate levels of a stress hormone which triggers depression and reduces the ability to learn.

Scientists exposed mice to a cycle of 3.5 hours of light and 3.5 hours of darkness, which previous studies have found does not disrupt their sleep.

The team found it caused the mice to develop depression-like behaviours, not learn as quickly and have raised levels of the stress hormone cortisol.

Samer Hattar, a biology professor at Johns Hopkins University, in the US, said: “I’m not saying we have to sit in complete darkness at night but I do recommend we switch on fewer lamps and stick to less intense light bulbs.” - Daily Mail