Light therapy, also known as phototherapy, is a treatment in which the patient is exposed to an artificial light source. It is used primarily to treat seasonal affective disorder (SAD)—the formal name of major depression that occurs during a certain time of year, usually winter—though 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 that 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 (someone new to the method may be given shorter initial treatments) and the strength of the light box. 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 effect.
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
The positive aspects of light therapy are as follows:
- generally few or mild side effects
- convenient (light boxes can be rented or purchased for home treatment)
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 as one step in an overall treatment plan for depression that includes other treatment methods 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 improve mood.”