Seasonal Affective Disorder – more than just SAD

Feeling blue since the holidays are over? Do the early nights get to you? You might have Seasonal Affective Disorder or SAD, a form of depression which begins in fall or winter.

Symptoms of SAD are similar to other forms of depression: low energy, problems concentrating, reduced interest in daily activities, moodiness, increased or decreased appetite, weakness and increased sleeping. Typically the problem resolves in early spring. It tends to recur every winter in affected people.

SAD is more common the farther one lives from the equator. Incidence is less than 2 percent in Florida residents and almost 10 percent in New Hampshire. It usually affects only adults and women account for 60-90 percent of cases. Researchers suspect there is a genetic predisposition—although studies to date are inconclusive.

It is theorized that the cause of SAD is related to reduced levels of light associated with winter. Although not completely understood, it may be due to improper daily cycling of melatonin and other body hormones or brain neurotransmitters. The features of SAD overlap with other medical illnesses so a doctor’s evaluation is needed for proper diagnosis.

There are several treatment options for SAD. Antidepressants are usually helpful, particularly the selective serotonin reuptake inhibitors or SSRI’s. Counseling in individual or group settings is also effective. Because of the correlation with reduced sunlight, light therapy has been studied and has been shown to be effective for SAD.

To be effective, light therapy must be bright enough and for a long enough time. Mild cases may respond to spending several hours outdoors on sunny days if temperatures are mild. If that is not possible, light boxes can be used.

Light intensity is measured by a unit called lux. Sunlight on a typical winter day in the northern United States is less than 2,000 lux at eye level. By contrast, indoor lighting registers approximately 100 lux on average. To be effective, a person with SAD should be exposed to about 3,000 lux at eye level for about 90 minutes or 10,000 lux for 30 minutes per day, preferably in the morning.

Commercial light boxes with standard fluorescent bulbs are available to produce the needed 10,000 lux. Full spectrum or ultraviolet light is not needed. When effective, a person’s mood improves in 4-7 days compared to 2-6 weeks with antidepressant medication. One need not look directly at the light, but it must shine on the face. Side effects are rare and include eye strain or mild headache and occasional agitation or excitability typically at higher brightness levels.

Light boxes are readily available online priced from $200-$300. Some possible sources include: http://www.northernlight-tech.com/eng/products.htm,

http://www.lighttherapyproducts.com/products_lamps.html

http://www.bio-light.com/lights.html

 

For more information on seasonal affective disorder, go to: http://www.websciences.org/sltbr/jama.htm