Seasonal Affective Disorder (SAD) is a type of depression that occurs during the winter months. You may have heard people talk about "cabin fever" or the "winter blues," but SAD is actually a seasonal form of depression. It's a very common problem that is more prevalent in the upper latitudes where the amount of daily sunlight decreases during the fall and winter months. The symptoms of SAD are actually very similar to depression, but depression does not abate during the spring and summer as SAD does. Fortunately there is a very effective treatment with minimal side effects. Learn more about SAD.
More about seasonal depression: