It is found in about 4 to 10 percent of the general population. It is a bigger problem for women than for men.
Women are about six times more likely to develop the disorder.
Up to 38 percent of people receiving treatments for recurrent depression report seasonal changes. Some symptoms of the illness include overeating with or without carbohydrate craving, weight gain, and oversleeping. It is believed that these winter depressions are due to the lack of light from the shortened days of winter. An effective treatment is phototherapy. Phototherapy involves the use of bright light.