Light therapy, also known as phototherapy, is a treatment in
which the patient is exposed to an artificial light source. The therapy
primarily treats seasonal affective disorder (SAD). Seasonal affective disorder
is the formal name of 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.
How It Works
Typically, light therapy is meant to compensate for the lack
of exposure to sunlight that is thought to be linked to SAD. The patient sits
near a machine called a light box, which emits strong light. The light usually
mimics natural sunlight though there are 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 a patient can 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.
Although light therapy has been shown to be effective, why
it is effective is still being studied. One theory is that light naturally
triggers serotonin (the “feel good” brain chemical) production in the brain.
Some experts believe that success with light therapy is due to a placebo
There are side effects to light therapy, including headache
and sunburn, but they are generally not serious. Most can be dealt with by
adjusting the duration and intensity of the sessions. Eye drops, nasal drops,
and sunscreen can also alleviate some symptoms.
People with sensitive skin, eye conditions, or a history of
skin cancer should consult a physician if considering this therapy.
Pros of Light Therapy
Light therapy has many positive aspects. Light therapy is:
- convenient (light
boxes can be rented or purchased for home treatment)
- generally has few or
mild side effects
Cons of Light Therapy
The negative aspects of light therapy are the side effects
and complications that could occur. These include:
- dry eyes and nose
- hypomania, an extended
period of heightened mood
What the Expert Says
Dr. Carl Vincent, a psychologist in Moline, Ill., suggests
that light therapy be used with other therapy treatments, such as psychotherapy
and/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