A light therapy lamp is used to treat Seasonal Affective Disorder (SAD), or winter blues, and other sleep and mood disorders. A light therapy lamp emits intense levels of light equivalent to outdoor light immediately following sunrise or just prior to sunset. This form of treatment first began in the early 1980s and its use increases each year.
The light therapy lamp consists of fluorescent bulbs in a box covered by a diffusing screen. The user sits close to the box while reading, eating, writing or working at a computer for time periods ranging from 15 minutes to two hours, either once or twice per day. Many users respond to light therapy within a week. Because of the seasonal nature of the disorder, a user begins treatment as the days become shorter, in the fall or winter, and continues until the days become longer in the spring.
Many users find that treatment in the early morning is most effective, but some users get better results with evening light. A light therapy lamp most likely adjusts a person’s internal clock, either by accelerating it or delaying it. Other theories suggest that light therapy lamps suppress melatonin or increase serotonin.
Symptoms of Seasonal Affective Disorder include depression and lethargy. Patients who have SAD experience depression symptoms, such as excessive eating or sleeping, cravings for starchy or sugary foods or social withdrawal, more often or more severely in the winter months. Those affected by SAD feel improvement in mood and energy level when the spring and summer months arrive. Young people and women are more likely to be affected by SAD, as are those who live in northern latitudes.
A light therapy lamp causes very few side effects, if any, in most people. Some users experience eyestrain or irritation, headaches or nausea when first beginning light therapy. A few users have difficulty sleeping or feel restless or wired because the light therapy signals their bodies to be overactive. For the most part, the only patients who should avoid using a light therapy lamp are those who have, or who might be at risk for, certain eye conditions. A light therapy lamp is safe for pregnant women and does not cause tanning because most systems reduce or block ultraviolet light.
The amount of light in a therapy lamp is measured in lux illumination. A 10,000 lux system has been used in clinical trials and appears to be most effective. A doctor should recommend and supervise the use of a light therapy lamp. Some patients who experience SAD also find that antidepressant medications alleviate the symptoms.