Seasonal Affective Disorder (SAD) is a type of depression related to the change of seasons. It usually affects people during the fall and winter months, though some experience it during the summer months. Researchers disagree on the exact causes of SAD. One theory is related to an internal clock in the brain.

The pineal gland, a tiny structure at the base of the brain, secretes melatonin when there is a lack of light. The increase of light at dawn tells the gland to switch off this secretion so we wake up. SAD sufferers appear to have something out of balance in their internal clocks. They may also have a genetic vulnerability to the illness, or the illness may be triggered by stress.

Symptoms of SAD include change in appetite, increased craving for carbohydrates, weight gain, decrease in energy level, fatigue, oversleeping, irritability, difficulty concentrating and social withdrawal. Other symptoms of depression may also be present, such as feelings of guilt, loss of interest in activities once enjoyed, feelings of hopelessness or physical aches and pains.

Treatment of SAD often involves light therapy. In light therapy, individuals expose themselves to bright light, either through a specially designed light box or a light visor, for at least 30 minutes per day. Light from standard light bulbs or fluorescent lights is not sufficient. Light boxes that produce the correct brightness needed are available from a variety of sources. Consult your health care provider to find a supplier who has a device that is appropriate for you.

Using tanning beds for light therapy is not recommended; tanning beds produce high levels of ultraviolet rays which can harm the skin and eyes. Side effects from light therapy may include eye strain, headache or inability to sleep, especially if the light is used late in the day. People with bipolar disorder or sensitive skin or eyes should use caution when using light therapy.

If you believe you may suffer from SAD, be sure to discuss any concerns with your health care provider. Do not try to diagnose yourself or begin light therapy without first talking to a health professional. Even if you do not develop all of the symptoms of SAD, you may be affected by the short, cold days of winter. Getting plenty of rest, eating regular, healthy meals and having a consistent exercise routine will help you maintain good health during the winter months and throughout the year.