In institutions such as the Mayo Clinic, SAD light therapy is considered a standard form of treatment for seasonal affective disorder, or SAD. Also referred to as a more serious form of “winter depression”, affected individuals suffer depression, lethargy, fatigue, and many other symptoms when shorter days and longer nights begin to raise their ugly heads in the fall and winter.
SAD has been recognized by the American Psychiatric Association’s diagnostic manual, in the DSM-IV as an official subtype of major depressive episode. Approximately 75% of those involved are women, with the most common age of onset being the thirties. A psychiatrist by the name of Norman Rosenthal in 1984 had published a paper SAD light therapy, with research still going on today in regard to it. From that moment in time in the early 1980s, SAD light therapy–also been called bright light therapy or photo-therapy–and over the years has been associated with the disorder SAD.
SAD light therapy needs about 30 minutes a day of daily light treatments–with the light treatments working best in the mornings with some using it in the evenings. The amount of light and when it is to be used depends a lot on the individual and the type of light box. A 10,000-lux light therapy box needs only 30 minutes a day of light treatment as a SAD light therapy, with the initial treatments requiring full spectrum lighting. More recent studies show that regular fluorescent bulbs can work as well, with UV or ultraviolet lighting needing to be filtered out as it damages the eyes and skin. But people still prefer the full spectrum minus the UV, as it is the closest to natural lighting available for SAD light therapy.
There are three key elements combined in SAD light therapy: intensity, duration, and timing. As many people know, light therapy is best used early in the morning as compared to using it in the evenings, as it has been known to disrupt sleep or cause insomnia. How long of a duration may range from 30 minutes to two hours, with initial doses as low as 15 minutes and working up. The intensity is a little more complicated, as the lux of the light box varies. The term “lux” refers to the measurement of light received at a specific distance from a particular light source, with the average light therapy box running between 2,500-lux and the typical 10,000-lux. To put this into more clear terminology, the average living room in the evening is about 400-lux, and the bright sunny day runs about 100,000-lux.