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Lack of Daylight May Cause Winter Depression

Military personnel can suffer from a form of depression known as seasonal affective disorder, which results from a lack of daylight during the cold, dark months of autumn and winter. (U.S. Army photo)

Winter blues can be a serious challenge to psychological health, especially if you’re sensitive to light. In this post on seasonal affective disorder from, the Military Health System talks with Cmdr. David Barry of the Deployment Health Clinical Center. Also check out the interview with Barry on feeling down after the holidays.

As days get shorter and colder and daylight becomes more fleeting during the winter months, many people experience a darkness of their own. The lack of sunlight can have a profound effect on people’s moods and psyches, leading to a form of depression known as seasonal affective disorder (SAD).

What is Seasonal Affective Disorder?

SAD is a common form of depression brought on by light deprivation that may affect people during the “dark days,” as it is sometimes referred to, of autumn and winter. Those who suffer from this disorder can experience sadness, feelings of hopelessness, lethargy and fatigue. These symptoms seemingly appear for no apparent reason and can be frustrating to those affected.

“It’s like a mild depression,” said U.S. Public Health Service Cmdr. David Barry, implementation division chief at the Deployment Health Clinical Center. “Those affected don’t find as much pleasure in things that they normally enjoy doing. They can have difficulty sleeping because the lack of light affects their circadian rhythms.”


People with SAD commonly report not wanting to get out of bed, a lack of interest in social activities, an increase in eating and difficulty focusing. One person Barry spoke with, who was affected by SAD, simply stated that “life becomes kind of dull.”

Most research suggests that SAD happens in autumn and winter due to lack of sunlight exposure. Lack of natural light can throw off people’s internal clocks, hormone production and serotonin levels, which all play major factors in the onset of SAD. Geographical location can also play an important role in the prevalence of SAD. Those living or stationed in cold areas with short windows of daylight, such as Alaska, might be more at-risk compared to those in sunny, warm climates.


SAD usually goes away on its own with time and during the months when the weather improves and sunlight becomes more prevalent, but available treatments can improve symptoms. One of the most common forms of treatment is light therapy. This form of therapy is usually achieved by exposure to artificial light through a light box used for short periods each day. These boxes emit either white or blue light rays that help simulate the effects of sunlight. Experts claim this form of therapy is very effective in combating SAD.

Those noticing possible symptoms should closely monitor any mental health changes during this “dark” time.

“Take a walk and go outdoors,” said Barry. “Be active and physical, and take the time to engage in things that you find pleasurable.”

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This page was last updated on: September 14, 2017.