seasonal affective disorder

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Related to Winter depression: Winter Blues, Seasonal depression

seasonal affective disorder

(SAD), recurrent fall or winter depression characterized by excessive sleeping, social withdrawal, depression, overeating, and pronounced weight gain. SAD effects an estimated 6% of Americans; for reasons not yet understood, 80% of those affected are women. Most children who are affected have a close relative who also has SAD or another psychiatric condition. The disorder particularly affects people who live in the upper latitudes.

Although the mechanism of the disorder is not perfectly understood, it is known to be a reaction to the biological effects of light on the body (see rhythm, biologicalrhythm, biological,
or biorhythm,
cyclic pattern of physiological changes or changes in activity in living organisms, most often synchronized with daily, monthly, or annual cyclical changes in the environment.
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). Daily, or circadian, rhythms help animals keep track of the seasonal changes in the environment, such as the shortening of days in winter, so that they can make the adaptive changes necessary for their survival in each season. Two substances, the hormone melatonin and the neurotransmitter serotonin, are a part of this process and are being studied for a possible role in SAD. Melatonin is secreted by the pineal glandpineal gland
, small organ (about the size of a pea) situated in the brain. Long considered vestigial in humans, the structure, which is also called the pineal body or the epiphysis, is present in most vertebrates.
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, which is in turn controlled by an area (the suprachiasmatic nuclei) of the hypothalamushypothalamus
, an important supervisory center in the brain, rich in ganglia, nerve fibers, and synaptic connections. It is composed of several sections called nuclei, each of which controls a specific function.
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; the hypothalamus, among other things, performs a clocklike function in the body. The eye's retinal nerves are connected to this area. Melatonin is secreted chiefly at night, and its secretion is suppressed by light. Secretion of the neurotransmitter serotonin declines in the winter and may undergo abnormal declines in those with SAD; concentrations of serotonin are increased by bright light. Serotonin is especially active in the hypothalamus. Decreased sensitivity of the retina has also been implicated as a cause of SAD.

Treatment with bright light (about five to twenty times brighter than normal lighting) often alleviates symptoms within a period of days. Unwieldy lighting paraphernalia has given way to smaller, portable light boxes and lighted visors. Doses range from 30 minutes to a few hours per day, often undergone in the morning to simulate the dawn.

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seasonal affective disorder

[¦sēz·ēn·əl a¦fek·tiv dis′ȯrd·ər]
(psychology)
A syndrome of annually repeating depressive symptoms (usually overeating, oversleeping, and carbohydrate craving) that are related to changes in the season and are responsive to light therapy. Also known as winter depression.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Results: Moderation analysis confirmed the moderating effect of coping strategies between seasonality and symptoms of winter depression. Findings revealed that the effective strategies of coping were problem -focused and emotion-focused coping which proved as protective factors in the seasonality and winter depression relationship.
(8) Can you describe an occasion when you found winter depression was especially hard?
Fall and winter seasonal affective disorder (winter depression)
It is thought that up to one in 15 of the UK population is affected by winter depression - or Seasonal Affective Disorder (SAD) - every year between September and April.
Also called winter depression, SAD is a form of depression that affects an estimated 10 to 20 percent of Americans when both its mild and severe forms are considered.
Experimental design and measures of success in the treatment of winter depression by bright light.
From winter depression to allergies, coughs, colds and flu, how do you keep yourself in tip top condition and feel on top of the world when the world seems so dreary and cold?
The 50-year-old Balsall Heath-born vocalist reveals that he suffers with Seasonal Affective Disorder - or SAD - a type of winter depression.
Up to a third of the population, in Britain at least, suffers from seasonal affective disorder, or SAD, also known as winter depression, according to MIND, a leading mental health charity in England and Wales.
Among those who do not suffer themselves, 44 per cent said they know someone who does succumb to winter depression.
These companies can easily be found through the internet by using light therapy or winter depression as a prompt.
The longer nights, especially when we switch from Daylight Saving Time back to Standard, and lack of sunlight affect our circadian rhythms, interrupt our sleep cycles, and cause fatigue and winter depression. There's no need to suffer, however, as research has shown that exposure to full spectrum lights for 30 minutes each day can alleviate these symptoms.