Seasonal Affective Disorder (SAD)

Seasonal Affective Disorder, or SAD, is how we refer to winter depression or the winter blues.  SAD typically begins in early to mid fall and lasts until spring, with the worst symptoms occurring during the darkest months.  By summer, most symptoms have disappeared. These symptoms may include sleep problems (such as oversleeping but not feeling rested and needing an afternoon nap); carbohydrate cravings and overeating; lethargy; physical symptoms (joint pain, stomach problems, lowered resistance to infection); and depressive symptoms (irritability, despair, misery, anxiety, frustration, withdrawal, hopelessness, guilt).  Although many people may have mild symptoms, many are severe enough to interfere in normal daily functioning.  Interestingly, the incidence of SAD increases with the distance from the equator, and more women are affected than men.  Children and adolescents are also vulnerable.

Research points to the lack of bright light in winter as the cause of SAD.  Research has proven that bright light affects the brain's chemistry, althouigh the exact mechanics are not yet known.  We can, however, be confident that SAD is not a psychosomatic or imaginary disorder.  A variety of theories have been explored, such as how our biological clocks depend on the light/dark cycle to regulate mood and the major function our eyes play in the regulation of our internal clock.

The role of melatonin is also being researched as a contributing factor.  Melatonin is a hormone secreted by the pineal gland, which is located at the base of the brain.  The amount of light seems to directly influence how much melatonin is secreted; more light produces less melatonin, and less light triggers more melatonin to be carried in the blood.  Melatonin causes body temperature to drop, which contributes to sleep.  Lower body temperature creates the need for increased carbohydrate intake in order to increase energy and body temperature. The role and use of melatonin in the treatment of SAD have been undergoing research for several years.

Bright light therapy is the most established treatment for SAD.  Some psychiatrists believe that a combination of light therapy and antidepressant medication is the best.  Special therapy lights have been designed for the treatment of SAD.  The amount of brightness needed is about five times brighter than a well-lit office.  The user does not stare directly into the light and can read or do other sedentary activities as long as light reaches the eyes.  A minimum of 15 to 20 minutes per day is sufficient to alleviate the symptoms of SAD.  Generally, if a few days of light therapy do not improve symptoms, the source of the depression is probably unrelated to light exposure, and a different type of treatment may be necessary.

If you believe that you suffer from SAD, please consult a mental health professional who can help you make that determination and recommend the best course of treatment.

For more information, go to http://www.mayoclinic.com/health/seasonal-affective-disorder/DS00195