While I have never bothered to be officially diagnosed, I am fairly certain that I suffer from Seasonal Affective Disorder, aka SAD. I began noticing the symptoms several years ago, and in recent years have experimented with possible treatments. While I still had some serious lack of motivation at times this past winter, it seemed to have gone better than most, so I think I'm on the right track with dealing with the problem.
I begin to notice the symptoms of SAD in the fall, when sunshine is less abundant and I spend less time outside. Rainy days tend to be especially bad for me. I find that snowy days aren't as bad, though, likely because we do not receive a lot of snow here. Usually the symptoms of SAD stick with me until springtime, when there is more sunshine and I'm able to get outside more often. A particularly rainy spring, however, can cause the symptoms to stick around a bit longer.
There is a lot of information available regarding SAD and possible treatments. For anyone looking for a solution, I would recommend researching many options, from multiple sources. Also, even though I didn't do so, it would be a good idea to discuss treatments with your doctor.
Since lack of sunlight seems to be the driving force behind my issues with SAD, I have been using a couple of treatments to address that. The first was to replace the light bulbs in my bedroom/office, where I spend most of my time, with full spectrum light bulbs. The bulbs that I chose are the ALZO 27w 5500k Compact Fluorescent. These bulbs are very bright, both because of their output and because of the color temperature of the light. The light is much whiter than a normal household bulb, which some may find annoying, but I find comforting since it is much closer to the color of sunlight. One note of warning, these particular bulbs are much larger than normal household light bulbs. That wasn't an issue for me, because I was installing them into an overhead light fixture that doesn't have a globe or shades on it.
The other aspect of not having access to sunlight is a decrease in Vitamin D production. I am a big believer that most people suffer from a lack of Vitamin D, and that the best way to remedy this is by being in the sun. However, in the winter, this isn't always practical. My solution is to take a Vitamin D-3 supplement during the fall and winter. This year I started taking it a bit earlier than before, and that seems to have helped. I am taking the Swanson Higher Potency Vitamin D-3 2000 IU, but I think that any quality Vitamin D supplement would be just as affective. I took a lower dosage, 1000 IU last year, but increased it this year, which also seems to have helped.
In addition to the Vitamin D I have also been taking St John's Wort. This was based on a suggestion that Andrea made, so I figured it couldn't hurt to try it. I have been taking the Swanson St John's Wort 375mg. It is suggested to take the supplement three times a day, but I can never remember to take it that often. I've only been taking it once each morning, which I'm sure limits the benefits. Because I haven't noticed any adverse effects, however, I will likely take it again next year, in case it was part of the reason things went better this past winter.
There is one last change I could make that I suspect would help, but I've been hesitant to try it since it conflicts with my desire to save on energy use. I believe that keeping the house warmer during the winter would help. I've noticed that when I'm cold, I feel somewhat sluggish, which I assume is related to the SAD. I do sometimes use a space heater to warm up my bedroom early in the mornings, but try to limit it because of the amount of electricity the heater uses. Perhaps one day, when we build a house, I can use a small fireplace to warm the house, or at least my room, on those particularly cold winter mornings. Until then I'll likely just stick to dressing in layers and hoping that my other solutions for dealing with SAD continue to get the job done.