As the temperatures drop and the days get shorter, many people's moods tend to get darker, experts say. During the winter months, about 5 percent of Americans suffer from seasonal affective disorder, or SAD. Some of the symptoms include depression and a drop in energy levels. People with SAD may have an increased appetite which could lead to weight gain. There are ways to beat the disorder, doctors say, including light therapy. Sufferers can spend half an hour each day in the sunlight or in front of special full-spectrum lights. If that doesn't help, people who believe they have SAD may want to talk to their doctor about counseling or medication.