People across the United States can all agree on one thing: winter has come. With a new severe storm coming just about every week, it seems like the snow will never melt. The days are cold and dark. The world outside has become a wash of grey and white. Driving is awful. Shoveling is exhausting.

There are plenty of reasons for one to feel down in the dumps these days. However, the misery that is slowly creeping into your heart may be caused by more than just the snow. Almost a quarter of all Americans experience some degree of Seasonal Affective Disorder (SAD). This mood disorder is caused by changes in weather patterns, in particular by the reduction of sunlight.

People who are generally consider to have normal mental health begin to feel lethargic and depressed. It becomes difficult to wake up in the morning and a tendency to overeat carbohydrates develops. SAD is categorized by feelings of hopelessness and a loss of interest in activities one used to love.

“Some people experience a serious mood change when the seasons change. They may sleep too much, have little energy, and may also feel depressed. Though symptoms can be severe, they usually clear up,” according to the U.S. National Library of Medicine.

Medical experts believe SAD is related to the level of exposure to sunlight. Indeed, Nordic countries tend to have very high instances of SAD diagnoses, as does Alaska. The established treatment for the disorder is to increase physical activity and the amount of time spent outdoors, especially on sunny days.

Another common treatment for SAD is to spend 30 to 60 minutes sitting under a lightbox, this is known as light therapy. A lightbox is a incandescent lamp which emits a “full spectrum light”- bright white light at 10,000 lux (lux is the standard international measurement for luminance). Antidepressants are occasionally prescribed but this is only for the most extreme cases.

If you are someone who feels depressed during the winter months, the most important thing to remember is that this will not last forever. It is February 18 – March is right around the corner. Soon, the snow will melt and the clouds will pass. Spring is coming.