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Light therapy, also known as phototherapy, is a treatment in which you’re exposed to an artificial light source. The therapy primarily treats major depressive disorder with seasonal patterns (formerly known as seasonal affective disorder, or SAD). This is a type of depression that occurs during a certain time of year, usually winter. Light is also used to treat other conditions, including sleep disorders and other types of depression.
Typically, light therapy is meant to compensate for the lack of exposure to sunlight that is thought to be linked to major depressive disorder with seasonal patterns. You’ll sit near a light box, which emits strong light. The light usually mimics natural sunlight, but there can be variations. A unit of measure called a lux gauges the amount of light used in a treatment. The standard output of a light box is between 2,500 and 10,000 lux.
Treatments usually begin in the fall and continue until early spring. Sessions commonly last from 10 to 15 minutes. The length of the session depends on how well you handle the treatment and the strength of the light box. Someone new to the method may be given shorter initial treatments. The more powerful the light box, the shorter the treatment session can be.
Why light therapy is effective is still being studied. One theory is that light naturally triggers the production of serotonin in the brain. Serotonin is the "feel-good" brain chemical. Some experts believe that success with light therapy is due to a placebo effect.
There are side effects to light therapy, including headache and sunburn. Usually, these are not serious. Most side effects can be dealt with by adjusting the duration and intensity of the sessions. Other treatments that can alleviate side effects include:
If you’re considering this therapy, you should consult a physician if you have any of the following conditions:
Light therapy has many positive aspects. The treatment can also be done at home using rented or purchased light boxes.
The negative aspects of light therapy are the side effects and complications that can occur. These include:
Dr. Carl Vincent, a psychologist in Moline, Illinois, suggests that light therapy be used with other treatments, such as psychotherapy or a drug regimen. "The idea is that it could be used as a supplemental therapy," Vincent says. "In addition to treatment, people suffering from depression in the winter months should try to be more active. Winter is a time when people tend to be more sedentary, and getting more exercise can help improve mood."
Light therapy is used to treat major depressive disorder with seasonal patterns, sleep disorders, and other types of depression. It is often effective, though doctors do not know exactly why. It can have a number of side effects, most of which can be effectively alleviated. Talk to your doctor if you feel light therapy might be useful for you.
Written by: Anthony Watt
Medically reviewed on: Dec 16, 2016: Timothy J. Legg, PhD, CRNP
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