GE Reveal Bulbs & Light Therapy

Seasonal Affective Disorder is a condition in which the reduced sunlight of the winter season produces a depressive mood change. According to the American Psychological Association, light therapy (phototherapy) is an effective treatment, but depends on exposure to the proper sort of light.

Understanding Sunlight

Sunlight is composed of many colors across an entire color spectrum. It is measured in Kelvin degrees. Full summer sunlight is 5500 to 7000 K. In the winter, because the sun is lower and travels at an angle through the atmosphere, it is both weaker in intensity and has a lower color temperature (5500 to 6000 K). The body responds to the lower amount of winter sun light by reducing the production of the hormone melatonin. By way of contrast, an ordinary incandescent light bulb has a color temperature of 2750 K, casting a much more yellowish light than sunlight.

Light Therapy

S.A.D. is frequently treated with light therapy. This consists of increased exposure to sunlight or to artificial lighting that mimics the full color spectrum of sunlight. Most treatments consist of sitting for 30 to 60 minutes in front of a full-spectrum lightbox upon awakening in the morning.

GE Reveal and Similar Lightbulbs

Most artificial lights produce light in a narrow spectrum range that is not suitable for S.A.D. treatment. Because ordinary incandescent lighting is rather yellowish, several manufacturers have developed product lines that are more daylight-like. These lights usually consist of bluish neodymium glass bulbs, and have the brand names "Reveal," "Chromalux" and "Pure Lite" among others. While the color temperature of neodymium bulbs are higher than regular incandescent lights (around 3200 to 4100 K compared to around 2750 K), they still fall far short of the color temperature of summer daylight (5500 to 7000 K), and have unnatural gaps in the output of their spectrum. This makes their use for treating S.A.D. medically problematic. Most studies have used lightboxes that contain special lights developed to mimic the sun's natural spectrum. However, there is some evidence from the National Institutes of Health that bluish light can effectively treat S.A.D.