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In much of the world, winter is a time for parties, celebrations, holidays, and general merry making. But not everybody joins in the fun. Some people experience winter as a time to eat more, get out less, lose interest in friends and family, and give up sex, because of the annual experience of depression caused by seasonal affective disorder.
What Is Seasonal Affective Disorder?
Seasonal affective disorder, sometimes known by its acronym SAD or S.A.D., is well-known illness that affects about 1% of the population in southerly locations like Florida and about 10% of the population in Canada, Europe, Russia, and the northern United States.
What Are the Symptoms of Winter-Onset Seasonal Affective Disorder?
As the days get shorter, people who have SAD want to sleep in longer. There can also be:
- Cravings for sugary and fatty foods, and increased consumption of alcohol.
- Weight gain, due to increased consumption of sugar, fat, and alcohol.
- Irritability, and conflicts with others.
- A feeling of heaviness in the arms and legs, or even all over the body.
- In children, chronic behavior problems.
People who have winter-onset SAD often become indecisive. They seem to develop attention deficit syndrome, but without the hyperactivity. In severe cases, they develop feelings of worthlessness or hopelessness or even become suicidal.
Using Bright Light to Treat SAD
The underlying cause of seasonal affective disorder is an overproduction of melatonin, the hormone that the pineal gland in the brain creates every night, when we shut our eyes in a dark place, to help us get to sleep. When darkness comes early in the evening, some people's brains make so much melatonin that they not only fall asleep in the evening but they don't want to get up the next morning.
In some people, melatonin production is highest in the evening, so they feel sleepy too soon. Treating their SAD is best accomplished with time in the sun in the late afternoon or a daily, afternoon session sitting under a sun lamp. In other people, the brain continues making melatonin even after it's time to get up. They need to get their sunlight or sun lamp time in the early morning. Almost any bright light will stimulate the brain as long as it generates visible blue light, which stops the production of melatonin.
Antidepressants take four to six weeks to work, and they carry significant side effects.
But if you feel tired all the time, how can you tell whether you have "morning" or "evening" depression from seasonal affective disorder? It turns out there is a simple test.