Here in North Dakota, season affective disorder is a fairly common problem during the winters because the winters last about 6 months and get extremely cold and snowy. It's also amplified by the fact that summers can get extremely hot, where it's always very sunny and close to or over 100ºF every day for about 4 months. So when we get sun, we get too much, and when we go without it, we go without sun too long. A few people who are close to me suffer from SAD, and it's nearly impossible to keep a healthy relationship with them during the winter because they're so manic, depressed, and desperate. In the summer they are stable and often pretty fun. These people also complain about their bodies so much more in the winter, complaining about stiffness, aching, laziness, and general pain.
I'm not from ND, and I don't think I've been here long enough to develop SAD. I also don't think I'm as prone to it because I've always been mostly mentally stable, no matter the circumstance. I lived on the Oregon coast for many years, and I actually loved how rainy it was. However, I do know that my CF is MUCH worse in winter here in ND. I think it's because my body is spending its energy trying to keep me warm and then I have no energy left to function with. I also find I have less motivation in the winter here, and waste my time so much more in the winter.
That said, I have been disappointed with myself in the last few days. The sun has FINALLY popped out, it's been around 60ºF for a few days. While it's mentally and physically felt really good, it hasn't given me more energy yet. It makes me want to go outside and lay in the sun rather than take a walk.