Light Up the Blues - Light Therapy for SAD (Seasonal Affective Disorder)

Medical Author: Melissa Stoppler, M.D.
Medical Editor: Barbara K. Hecht, Ph.D.

Daily therapy with a light box is a valid treatment that can provide relief for sufferers from seasonal affective disorder (SAD). The relief obtained by exposure to light is comparable to that achieved with antidepressant medications, according to a review of multiple studies.

Seasonal affective disorder (SAD) is a common form of depression. It affects an estimated 4-6% of the population, or about 1 in every 25 people. For reasons that are not known, women have SAD four times as often as men.

The symptoms usually begin in early adulthood and characteristically occur at a specific time of the year. These symptoms may include feelings of sadness and lethargy (sluggishness), changes in appetite and weight, and increased sleepiness. SAD sufferers may also encounter increased difficulties in interpersonal relationships.

The vast majority of people with SAD experience it during the winter months (starting in the late fall), but summertime depression is also a recognized form of SAD. SAD during the winter is believed to result from an inadequate amount of exposure to sunlight, although the exact mechanism by which low light levels result in depression is unknown.

Researchers at the University of North Carolina did what is called a metanalysis. They reviewed and analyzed all previously published studies on the efficacy of light-box therapy.