What is SAD and how does Light Therapy Help

Seasonal Affective Disorder, or SAD, is a form of depression that follows a seasonal pattern. It appears to result from changes in the length of day, although more than lost sunlight may be involved. The disorder tends to last longer and be more severe at higher latitudes where is greater difference between the long days of winter and the short winter ones.
However, the influence of light doesn’t completely explain SAD. Thus far, no studies have demonstrated a causal link between a reduction in daylight hours and the development of the disorder. And various experiments have shown that some of the body’s cycles persist in the absence of light cues. Nevertheless, light therapy is uniquely, although not universally, effective in treating “winter depression.” Light therapy is usually the first therapy recommended for a person suffering this type of depression, provided they are not suicidal.
The “light box” contains florescent lights mounted on a metal reflector. There are several light box models. Some are designed to sit on a tabletop or desk, and others clamp onto a stand. They differ in size and portability. Some are small enough to be packed in a travel bag. They can also be adjusted for height and intensity.
Other light therapy devices include a battery operated light visor worn on the head, and the dawn simulator, a bedside light on a timer that gradually illuminates the bedroom in the morning to create an artificial early dawn.
The cost of light boxes is usually covered by insurance. (Summarized from Harvard Women’s Health Watch, Feb. 2005, Vol. 12, No. 6, pp