Wintertime blues are common for those of us living in the northern latitudes of the U.S., and they usually begin when the days get shorter, darker, and greyer. The clinical name is Seasonal Affective Disorder or SAD. It seems to be more common in women but more severe when it occurs in men. There may also be a genetic component, as with other forms of depression, that runs in families. Generally speaking, with SAD the changing levels of light impact the pineal gland and the production of both serotonin and melatonin, which may be connected to the development of depression in some people.
Symptoms of SAD may include any or all of the following:
- Carbohydrate cravings, appetite changes, weight gain
- Loss of energy, fatigue
- Depression, hopelessness, anxiety
- Increased sleepiness and sleeping
- Loss of interest in activities and social withdrawal
- Difficulty concentrating
SAD may increase the risk for a major depressive episode, which can lead to social withdrawal, work problems, substance abuse, and suicidal thoughts.
Since the cause of SAD seems to be a lack of light, it makes sense that adding light may address the underlying cause and provide support. A number of clinical studies have now shown the effectiveness of light therapy in the treatment of SAD. A light box delivering 2,000-10,000 lux for 30-120 minutes daily during the winter is typical.
In addition, different color temperatures of “full spectrum” light have been studied and the use of the light box both morning and evening seems to work best. Bright light seems to increase serotonin levels, so it is no surprise that light therapy has been shown to be as effective as Selective Serotonin Reuptake Inhibitor (SSRI) antidepressant medications, which raise serotonin levels, in a number of studies.
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