As the days grow shorter, people are exposed to far less sunlight, particularly here in Urbana-Champaign. This can lead to Seasonal Affective Disorder, said Holly Mirell, Ph.D., at Carle Clinic in Urbana.

"Seasonal Affective Disorder is more than the occasional feeling blue when there's cloudy weather," Mirell said. "It is a documented disorder resulting from a lack of sunlight."

Seasonal Affective Disorder leads to a lack of functioning in work or at home and also a feeling of extreme lethargy, she added.

Difficulty getting out of bed, sadness, and the craving of carbohydrates can all stem from the disorder. Another problem with the disorder is that those afflicted with the disorder have reduced slow-wave sleep, which is the deepest sleep, according to the Archives of General Psychiatry.

The disorder most often occurs between September and the end of December, but it can begin as early as July as the days grow shorter after the summer equinox.

Some people are skeptical of whether the disorder actually exists, but research has shown otherwise.

According to a study by the Uniformed Services University of the Health Sciences in Bethesda, Md., Seasonal Affective Disorder is much more prevalent in the winter at northern latitudes.

Results were much higher in New York and New Hampshire than in Florida. Some of the highest recorded incidences of Seasonal Affective Disorder are in Fairbanks, Alaska, where 9.2 percent of subjects tested had the disorder, according to an American Journal of Psychiatry study.

Women are more susceptible to the disorder, according to the American Journal of Psychiatry study.

There are a number of treatments for Seasonal Affective Disorder.

One possible treatment is to gain more exposure to full-spectrum light. This can be achieved by using light boxes, which can be purchased from a medical supply company, or the full-spectrum lights that are used for art display, Mirell said. One should undergo light treatment in the morning in order to "set your clock," Mirell said.

If the condition is particularly bad, one should consult a physician, who can prescribe an antidepressant, she added.

One should be sure to structure one's day in order to rise early enough to get some natural sunlight, Mirell said. Increasing good proteins and decreasing the intake of simple sugars can help treat the disorder, she added.

"Having structure in your day is important," Mirell said.

Coffee dates, visiting with friends and other social engagements all help to combat the disorder, she added.