Well, it looks like there just may indeed be a connection between depression and the amount of light when a person is sleeping. Live Science has an interesting piece on studies that show a correlation between light and sleep and depression. See http://www.livescience.com/health/night-light-depression-brain-101117.html for their piece along with their suggestion to sleep in a dark room.

It seem that those who sleep with no light tend to be healthier than those who have light on when they sleep (about the equivalent of having a tv on in a darkened room while you sleep).

Not the best news to those of us who prefer a night light.

– Brian