Depression Health Center

Understanding Seasonal Affective Disorder (SAD) -- Diagnosis and Treatment

How Do I Know If I Have Seasonal Affective Disorder?

Because no lab test exists for SAD, diagnosis is made on the basis of the patient's history and should be made by a psychiatrist experienced with the disorder. Illnesses with similar symptoms that must be ruled out are underactive thyroid function, hypoglycemia, chronic viral infections, and chronic fatigue syndrome. In children, abuse and separation anxiety should be considered, and in adolescents, substance abuse and anxiety disorders must be ruled out in making a determination of SAD. Doctors can diagnose SAD based on standards developed by the American Psychiatric Association.

Various forms of "measuring" tools are available for depression. They are frequently used in a primary care physician's office for early detection of subtle signs of depression. These tools include the:

• Beck depression inventory
• Hamilton depression inventory
• Zung depression rating scale

What Are the Treatments for Seasonal Affective Disorder?

The most effective treatment for SAD is light therapy, sometimes combined with antidepressant drugs, psychotherapy (talk therapy), or both.

Light therapy, sometimes called phototherapy, can be used in different ways and may employ different types of light boxes, light visors, and lamps. All are designed to bring in extra light to the eyes. Check to be sure a light box filters out harmful ultraviolet light.

In the most common form of light therapy, you sit before a light box of strong fluorescent light covered with a plastic screen to block ultraviolet light (10,000 lux - about 10 to 20 times brighter than ordinary indoor light) for periods varying from 15 minutes to 1 1/2 hours a day. You place the box on a table or desk where you can do paperwork, read, or make phone calls. You do not need to look directly into the light.

Other light sources include larger boxes that stand on the floor, visors with lights attached, and dawn simulators -- lights programmed to turn on by your bed on winter mornings before dawn.

Light boxes can be purchased for several hundred dollars at special stores. Experts warn against constructing your own light box because of possible damage from ultraviolet light.

Light therapy is safe and generally well tolerated. Minor side effects of light therapy include eye strain, headache, irritability, fatigue, and insomnia.

Since SAD is a form of depression, many different types of antidepressants have been used. The novel antidepressant Wellbutrin is the only drug approved by the FDA for the treatment of SAD.  Other antidepressants, such as selective serotonin reuptake inhibitors (SSRIs, such as Paxil and Prozac), are also often used in the treatment of SAD, either alone or in conjunction with light therapy.

In extremely  severe cases of depression, especially when the patient is suicidal or has psychotic symptoms (delusions or hallucinations), electroconvulsive therapy may be used. In this treatment method, finely controlled electrical charges are used to induce seizure-like activity in the brain.

The role of other forms of brain/nerve stimulations in the treatment of SAD -- such as vagus nerve stimulation (VNS) or Repetitive Transcranial Magnetic Stimulation (rTMS) -- has not yet been well established.