Do you experience increased moodiness and marked decrease in energy throughout the winter months? Is it difficult to relate these feelings to any specific reason or event? You may be suffering from winter depression, which is know in the medical field as Seasonal Affective Disorder (SAD).

What is SAD and Who is Affected?

SAD is a change in mood and behavior due to seasonal changes. An estimated 6% of the U.S. population suffers from serious depression related to the time of year. Researchers at The National Institute of Mental Health estimate that another 2% of the population suffers from a mild version of SAD. SAD is also four times more likely to affect women and the condition is more common the further north you live.

Research Findings and Possible Causes

Research into the biological causes of SAD started 30 years ago with experiments on the effects of light-dark cycles on the body's internal clock. In research on animals, winter-type lighting schedules were shown to produce hibernation. We know that workers who move from day to night shift work experience a period of re-adjustment to light levels. There appears to be a direct correlation between diminished winter daylight and depressed moods.

New research suggests the SAD disorder is related to visual differences in 6 to 14% of the population - the majority of them women (New York Times, 5/12/92). In this study, the retina at the back of the eye has been found to be unusually insensitive to dimmer winter light. The retina is the beginning of a series of nerve pathways to the hypothalamus, the part of the brain thought to contain the body's "biological clock". The reduced light wave stimulation in the affected individuals appears to disrupt the hormone cycle. People sensitive to these effects often experience depression during seasons of dimmer and shortened daylight hours without understanding why they feel depressed.

How Do You Know if You Have SAD?

The most pervasive symptom is fatigue, accompanied by foggy-headedness for several hours each day. Symptoms may also include any or all of the following:

• Recurrent anxiety as winter approaches
• Lethargy and a desire to sleep more
• Craving for sweets and starchy foods
• Weight gain
• A wish to be alone
• Low sex drive
• Feelings of persistent sadness, irritability, anxiety

The difference between seasonal depression and the blues, or even chronic depression, is that recovery depends upon increased amounts of light. Just as winter darkness causes depression, bright summertime light levels may bring on an unusually elevated mood.

Assessment and Treatment

Since there is no lab test for SAD, diagnosis is based on your history of yearly mood changes. The Seasonal Assessment Questionnaire (SAQ) assesses sleep patterns, social activity, mood and weight changes as well as energy level variations.

Treatment for SAD consists of sitting a specific distance from a bank of special fluorescent tubes for one to six hours each day. The level of illumination is about five times that of a well-lighted room and is carefully controlled in laboratory situations. The regimen can be followed at home with careful instruction and compliance.

If you think you suffer from SAD and want more information, consult your family physician or contact your EAP counselor.

Additional Resources

The National Institute of Mental Health
9000 Rockville Pike
Bethesda, MD 20892
301-496-0500
www.nimh.nih.gov

EnviroMed
1600 S.E. 141st Ave.
Vancouver, WA 98683
1-800-222-DAWN
www.bio-light.com/articles/html

The Sunbox Company
19217 Orbit Dr.
Gaithersburg, MD 20879-4149
1-800-548-3968
www.sunbox.com

The Society for Light Treatment and Biological Rhythms
174 Cook St.
San Francisco, CA 94159-1687
www.sltbr.org

Recommended Reading:

"Winter Blues", Norman Rosenthal, Guilford Press, 1998.

Written by Helene W. King, Ph.D., CEAP
Edited by Mary McClain Georgevich

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