That's Fit

Seasonal Affective Disorder, otherwise known as "SAD," is a legitimate and diagnosable form of depression that affects as much as 10 to 20 percent of the population every year. Shorter days and less exposure to natural light seem to be the culprits, especially as some cases have even been seen in patients who work long hours in windowless offices.

Unlike a diagnosis of major depression, SAD is not usually treated with medication. The FDA did recently approve the use of Wellbutrin XL for SAD, but phototherapy continues to be the most popular treatment -- with other methods like exercising, taking vacations to sunny locations, and meditating also being very effective.

Symptoms of SAD can be many things, but some of the most common include moodiness, decreased interest in social activities, irritability, and increased fatigue/sleep. The interesting thing? The seasons can affect people the opposite way too. Spring-summer hypomania (spring fever) is also a real condition characterized by increased energy, decreased appetite, and decreased sleep. But, obviously, nobody minds coming down with that one!