SAD is a form of depression that occurs in the fall and winter months, probably in response to the fewer hours of daylight. Symptoms usually begin in late fall or early winter and go on until the following summer. A less common type of SAD, summer-onset depression, usually begins in the late spring or early summer and continues until the following winter. Between four percent and six percent of people in the United States are believed to suffer from SAD. Another 10 percent to 20 percent experiences a milder form of winter-onset SAD. This disorder is more common in women than in men. Although some children and teenagers are affected, SAD usually occurs in people between 18 and 30 years of age.
What are the symptoms?
Symptoms are typical of depression: fatigue, lack of interest in normal activities, social withdrawal, weight gain, and a craving for carbohydrate foods. However, some of these symptoms occur as a result of physical disorders including an underactive thyroid, hypoglycemia, infectious mononucleosis and other viral infections. If you think you have SAD, be sure to consult with your physician to make sure that your symptoms aren’t due to something else.
The symptoms of SAD that occurs in the summer are typically somewhat different from the more common type of winter seasonal depression. They include anxiety, insomnia, irritability, agitation, weight loss, poor appetite and increased sex drive.