Seasonal affective disorder, abbreviated SAD, is a disturbance of mood that occurs with a change in season. It usually occurs during the fall or winter. For this reason, it is sometimes called winter depression. The most common symptoms include sadness, irritability, sleeping and eating much more than usual, poor concentration, fatigue, aches and pains, and severe anxiety. The symptoms typically go away in the spring. Doctors make a diagnosis of SAD only when symptoms occur in three different years or at least two years in a row.
SAD results from the shortening of the period of daylight during fall and winter. In the Northern Hemisphere, SAD is usually more common among people who live farther north, where winter daylight is shorter.
Most victims of SAD suffer their first episode as teenagers or young adults. For some, SAD may begin during childhood. Students with SAD may do well at the beginning and end of the school year, but they may perform poorly in winter months. Teachers and parents may mistake SAD symptoms for misbehavior. Similarly, adults with SAD may have poor job performance during the fall and winter months.
SAD may be treated with high-intensity artificial light or with medication. Treatment with bright light requires special fluorescent tubes that emit light similar to sunlight. SAD patients receive the light treatment for a half an hour to one hour each day. Improvements in the patient’s condition generally occur after a few days to two weeks. SAD also can be treated with antidepressant drugs.
