Seasonal Affective Disorder

Seasonal affective disorder, or SAD, also known as winter depression is an affective, or mood disorder. Most SAD sufferers experience normal mental health throughout most of the year, but experience depressive symptoms in the winter or summer. SAD is rare, if existent at all, in the tropics, but is measurably present at latitudes of 30°N (or S) and higher.

What is Seasonal Affective Disorder?

What is Seasonal Affective Disorder? Some people suffer from symptoms of depression during the winter months, with symptoms subsiding during the spring and summer months. This may be a sign of Seasonal Affective Disorder (SAD). SAD is a mood disorder associated with depression episodes and related to seasonal variations of light.
SAD was first noted before 1845, but was not officially named until the early 1980’s. As sunlight has affected the seasonal activities of animals (i.e., reproductive cycles and hibernation), SAD may be an effect of this seasonal light variation in humans. As seasons change, there is a shift in our “biological internal clocks” or circadian rhythm, due partly to these changes in sunlight patterns. This can cause our biological clocks to be out of “step” with our daily schedules. The most difficult months for SAD sufferers are January and February, and younger persons and women are at higher risk.

Possible Cause of seasonal affective Disorder

Possible cause of seasonal affective disorder - Melatonin, a sleep-related hormone secreted by the pineal gland in the brain, has been linked to SAD. This hormone, which may cause symptoms of depression, is produced at increased levels in the dark. Therefore, when the days are shorter and darker the production of this hormone increases.

seasonal affective Disorder Treatments

Treatments - Phototherapy or bright light therapy has been shown to suppress the brain’s secretion of melatonin. Although, there have been no research findings to definitely link this therapy with an antidepressant effect, many people respond to this treatment. The device most often used today is a bank of white fluorescent lights on a metal reflector and shield with a plastic screen. For mild symptoms, spending time outdoors during the day or arranging homes and workplaces to receive more sunlight may be helpful. One study found that an hour’s walk in winter sunlight was as effective as two and a half hours under bright artificial light.
If phototherapy doesn’t work, an antidepressant drug may prove effective in reducing or eliminating SAD symptoms, but there may be unwanted side effects to consider. Discuss your symptoms thoroughly with your family doctor and/or mental health professional.

When SAD was first investigated there was hope that the apparent link between an animal model (photoperiodism) and treatment (with bright light exposure) would soon lead to confirmation of an underlying etiology for winter depression. The past decade of research has shown SAD to be more complicated and heterogeneous than first thought, and the mechanism of light therapy is proving as elusive as that of antidepressant medications. Further research is therefore needed to determine the pathophysiology of SAD and the specific effects of light therapy.

References
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