Seasonal affective disorder or SAD is a type of depression that reoccurs with a seasonal pattern. The symptoms usually begin in fall and continue into winter months.
About 10 million adults suffer from seasonal affective disorder in the United States. Women are more likely affected than men. About 75% of people with seasonal affective disorder are women.
Signs and symptoms of SAD include:
* Feeling sad or depressed
* Loss of interest
* Changes in appetite; usually eating more with cravings for carbohydrates
* Change in sleep; usually sleeping excessively
* Extreme fatigue and lack of energy.
* Weight gain
* Inability to concentrate or to make decisions
* Anxiety, irritability.
* Feeling guilty, hopeless or worthless
* Thoughts of death or suicide attempt
It remains unclear what is the specific cause of seasonal affective disorder. It is hypothesized that the reduced level of sunlight in fall and winter may disrupt your circadian rhythms or biological clock, cause a drop in serotonin level and disrupt the balance of melatonin level. These changes can lead to symptoms of seasonal affective disorder.
Fortunately, light therapy is available as an effective treatment for individuals with SAD.
Light therapy involves exposure to light box with a light intensity of 10,000 lux. Lux is a unit of illumination, which measures the intensity of light. One lux is equal to one lumen per square meter. Light level in office is 300-500 lux. The light level of direct sunshine is around 100,000 lux. You should get the light therapy early every morning after you wake up. The light box should be placed about 2 feet away from you at the level of your face. You should not look directly into the light box to avoid eye damage. Instead, you should let the light enter your eyes indirectly. Each session of treatment lasts about 30min.
Symptoms usually improve within a few days of treatment. Sometimes it can take a few weeks. It is important to continue the treatment throughout the season because symptoms of SAD will recur if you discontinue light therapy in the middle of the season.
People with seasonal affective disorder need to begin light therapy in early fall. The treatment should continue until spring or summer when symptoms of SAD resolve.
Light therapy is typically safe and well-tolerated. Side Effects include:
Eyestrain
Headache
Nausea
Irritability or agitation
People with bipolar disorder may experience mania and/or hyperactivity.
Although you do not need a prescription to purchase a light box, you should consult a health care provider before starting light therapy to see if the treatment is safe for you. Several medical conditions can make people more sensitive to light. They include systemic lupus erythematosus, taking certain antibiotics and anti-inflammatory medications, cataract, glaucoma, retinal disease, diabetes. Light therapy may trigger hypomania or mania, people with bipolar disorder should use light therapy under medical supervision
Most health insurance plans do not cover the cost of the light box for light therapy.
The price of a light box ranges from $20 to several hundred dollars, When you buy a light box, make sure you select a light box labeled with 10,000 lux and UV-free.
Finally, I would like to mention that light therapy can also be used for other medical conditions besides seasonal affective disorder
* Light therapy can be used to treat other types of depression that don’t occur seasonally. The treatment may enhance the effectiveness of anti-depression medication or counseling and allow you to lower the dose of anti-depression medication. Light therapy may help you avoid anti-depression medications during pregnancy or while breast-feeding.
* During periods of work shift switching, light therapy helps shift your circadian rhythms and make the adjustment easier.
* Light therapy helps reduce the symptoms of Jet lag
* Studies have shown that light therapy can help people with dementia increase night-time sleeping and decrease daytime sleeping.
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