The Cause and Treatment of Seasonal Affective Disorder

Correlations between state of mind, degree of energy and time of year are well-documented. Especially in high latitudes (50°N or S) people commonly experience lower energy levels during the winter. Colds and flu season peaks during this time, and many get less outdoor exercise at this time of year.

"Winter depression" is thought to be related mostly to an absense of light as opposed to changes in temperature. Because of this, Seasonal Affective Disorder can be found even in mid-latitude places with mild winters, as is the case with Seattle. Extended periods of cloudy weather can also trigger SAD. Incidents of general winter blues can usually be lessened or alleviated by working out and additional outdoor activity, especially on sunny days. SAD, however, is more serious, sometimes resulting in clinical depression, which may require hospitalization.

Various causes have been suggested. One theory is that SAD is related to a lack of serotonin and that exposure to full-spectrum artificial light may improve the condition by stimulating serotonin production. Another theory is that melatonin produced in the pineal gland is the primary cause. There are direct connections between the retina and the pineal gland however some studies show that melatonin levels do not appear to differ between those with and without SAD. Light therapy appears to be effective in treating SAD, but the exact mechanism of the effect is still unknown.

"Full-spectrum" light bulbs and "sunlight lamps" are available for those suffering from Seasonal Affective Disorder. The most accepted light therapy is the use of a bright light box for 30-60 minutes each morning. Light boxes are far more bright than standard light bulbs.

Recently, one much reported study seemed to indicate that focusing a bright light behind an affected person's knees would be helpfull, however when this was attempted in a large-scale study, this was disproven.

Medication is a more recent treatment. SSRI (selective serontonin reuptake inhibitor) treatment has been proven an effective treatment for a Seasonal Affective Disorder. SSRIs are antidepressants such as Prozac, Zoloft and Paxil.

Controlled studies have also shown "dawn simulation" to be as beneficial as bright lights in treating SAD, but with less side effects and more convenience. A special device called a dawn simulator slowly brings up standard bedside lamps during the hour before the individual wakes up.