Daylight saving time begins three weeks earlier this year and lasts one week longer -- welcome news for people who relish the extra afternoon light to garden, ride a bicycle, walk the dog or just take out the trash when they can still see the curb.
But the extension, which begins Sunday, could actually make millions of Americans feel less sunny. For those people -- suffering from seasonal affective disorder or its milder cousin, winter blues -- the corresponding reduction in morning light may worsen or lengthen their depression, doctors and mood experts say. "We're very worried about it," says Michael Terman, director of New York-Presbyterian Hospital's Center for Light Treatment and Biological Rhythms. "It's the early morning light exposure that allays the symptoms of winter depression. The later the sun rises, the more likely we are to get depressed."
Early morning light sets the body's clock to gear up for the day's activities, but the later sunrise in the winter -- and a society based on the clock instead of nature -- causes a delay in the normal cycle, says Terman. For some people, this can lead to winter-induced depression, known as seasonal affective disorder.
Such depression usually creeps up in late fall, slams down hard in January and February and lifts in early May. Besides a poor mood, symptoms include low energy, problems sleeping, fatigue, weight gain, reduced concentration and increased appetite, especially for carbohydrates.
Most people with the condition feel their normal selves in the summer months.
"In the summer, these same people are dynamos," says Dr. David H. Avery, a professor of psychiatry and behavioral sciences at the University of Washington.
About 3% to 5% of Americans are thought to have seasonal affective disorder, says Terman, although it's far more common in the northern latitudes than in the Sunbelt. An additional 15% to 20% of people experience a lesser form of the disorder, called winter doldrums or winter blues. They are not diagnosed with clinical depression, but they clearly don't feel as chipper in the winter months.
Even the residents of sunny Southern California are not immune. Byron Acevedo, 36, says he feels depression coming on each October. "It's amazing how it affects me," says the computer technician, who works in Glendale. "I realize the days are getting cold and dark. I just feel sad."
