Research on mice conducted at Johns Hopkins University has shown that exposure to bright lights late at night (lights from sources such as computer screens and television) leads to an increased risk of depression and learning disorders. In the tests, the mice’s cortisol levels were reported to have increased. This hormone is widely known to be associated with conditions such as depression and learning disorders. The symptoms dissipated with common antidepressants. The depression symptoms were prevalent because there are photosensitive cells in the mice’s eyes (as well as ours) that are activated by this light. These cells impacts moods, learning, and memory.
Read full article here Using Computers At Night Can Cause Depression