Originally Posted by stadjer

i did night shifts in this time of year once, at the post service which was very busy with christmas cards. We often went to a bar afterwards for a few drinks but i didn't stay long enough to go home with daylight, when i got out of bed it was dark again. I'm mentally very stable and upbeat, but after two weeks of hardly any daylight, not even through a window, i wasn't doing fine. Not sad, depressed or whatever, still upbeat but extremely indifferent about anything.

So i quit, since then i'm very much more aware of the positive effects of daylight on my mental condition, it's not only good for my mood but also for concentration, energy and initiative. Of course people get together a lot this time of year to compensate lack of light with human warmth and i'm sure that works for at least the mood, but you've got to make that happen.