Jennifer McPhee
Northern News Services

Yellowknife (Nov 16/01) - As the weather gets colder and darker, so do some people's moods.

Seasonal Affective Disorder (SAD) is a clinical disorder caused by a lack of sunlight absorbed through the eyes. Symptoms include depression, oversleeping and cravings for carbohydrates.

About two per cent of Canadians suffer from SAD and 10 to 14 per cent experience a milder form of the disorder called the "winter blues."

"The further you are from the equator, the greater the chance you'll suffer from SAD," said Mike Mann, general manager of the Canadian Mental Health Association, NWT Division.

"It's like a continuous bout of the flu," said Mann.

The onset of SAD typically starts in October and can last until the beginning of spring.

To combat the problem, the Canadian Mental Health Association is lending out its sun lamp for two-week periods. All you need is a doctor's note and a security deposit.

The precise cause of SAD is still a mystery. However, scientists believe that high light intensity stimulates the brain to produce more serotonin, a neurotransmitter known to counter depression.

It also helps cut back on the amount of melatonin released during the day.

Melatonin is a substance produced by the brain that makes us sleepy come night time. Bright light in the morning stops its release.

But on dark days, when there isn't enough light, the gland may keep producing melatonin, which could be why SAD sufferers oversleep or wake up feeling unrefreshed.

Mann compared SAD to the hibernation reflex syndrome in some animals.

He said he's even heard of an instance in which a dog appeared to suffer from SAD, but perked up after bathing under high-intensity light.

Many people who have SAD feel more alert and alive after using the lamp for two weeks.

But Mann said lamps don't work for everyone.

"If it doesn't work, one should see a doctor and get prescribed for anti-depressants," he said.