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S.A.D (Seasonal Affective Disorder)
What is S.A.D, and When Was It Discovered?

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What is S.A.D, and When Was It Discovered?
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What Is S.A.D.

Our biochronological clock is set to a 24 hour period, which incorporates the aproximate time of the rising and setting sun.
The light from the sun (and only natural light) can create melatonin, which is released during the night. The amount of light recieved during the day affects the amount of melatonin created during the night. However, this is an inverse effect, or in other words, the more sunlight during the day, the less melatonin released during the night, and vice versa.

The more melatonin released into your body, the harder it is for your body to go from a sleep to wake state of being.
In the winter, the days grow shorter (in the northern latitudes moreso), and more melatonin is released during the longer night. This causes the person to go through a drowsy state, become lathargic and ultimalty depressed during the winter.

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Because of this increased level of melatonin, some of the population experience an inablility for their internal clocks to reset to the new aproximate times of night and day, thus they become affected by high melatonin and S.A.D.

History of S.A.D.

-Hippocrates postulated centuries ago that these changing patterns of light and dark might cause mood changes

-Seasonal downward mood changes of late fall and winter have been the subject of many sorrowful turn-of-the-century poems of lost love and empty souls.

-Only recently have the effects of sunlight on mood swings been scientifically proved through research and study. The result: a mental disorder called S.A.D.

SAD affects approximately 35 million Americans, 10 million with the disorder and 25 million with subsyndromal SAD

While most people who live in northern latitudes tend to experience some mild depression symptoms related to seasonal changes, up to five or ten percent of the general population may be affected by one or more of the diagnostic symptoms of Seasonal Affective Disorder

There is a clear link between latitude (probably proportional to the amount of exposure to daily direct sunlight) and the susceptibility to Seasonal Affective Disorder. For example, in Florida, less than 1% of the general population is thought to be affected by SAD, while in Alaska, the percentage of affected people may be as high as 10%