Seasonal affective disorder, a.k.a. "winter blues," is a form of depression that arises during the winter months, when days are short and dawn comes late.
About 5 percent of the population suffers from SAD, Dr. Alfred Lewy, professor of biological psychiatry at Oregon Health and Science University and a SAD specialist, tells CBS News. About 15 percent of the population has a mild form of SAD, he says.
If you or someone you care about seems to have SAD, you should know there are simple ways to get help. Keep clicking to find out more about treating SAD.
What causes SAD? The latest thinking is that shorter days cause an individual's inner time clock, or circadian rhythms, to fall out of sync with the time on the clock. Instead of waking up after dawn breaks, we wake up in darkness - and as a result feel sluggish and sad for the rest of the day. "It's like having jet lag for five months," Dr. Lewy says.
Seasonal affective disorder is four to five times more common in women than in men and seems to run in families, according to Dr. Lewy. In addition to sadness, SAD can cause carbohydrate cravings, weight gain, social withdrawal, and other problems.
What can be done to ease symptoms of SAD? The same sorts of steps that can be helpful for other forms of depression often seem to help in cases of SAD. Regular exercise, eating a well-balanced diet, spending time with friends and family, getting enough sleep, and avoiding excessive drinking can all provide some measure of relief.
Exposure to bright light can also help.
Someone who might have SAD can try spending time outdoors as soon as possible after rising. Even on a cloudy day, 15 to 30 minutes of outdoor light might be enough to reset your body's time clock and boost your mood. Indoor lighting just isn't bright enough.
Another way to get more of the bright light the body needs is to move someplace sunny. Settling closer to the equator will mean earlier dawns and more hours of sunlight each day.
Can't move? Maybe you could find a sunny place to vacation.
Since moving or taking an extended vacation is often out of the question, Dr. Lewy and other SAD experts recommend light therapy, which involves sitting in front of super-bright lights shortly after waking (or in some cases, in the early evening).
So-called "light boxes" are available from various manufacturers. SAD sufferers often feel better when they get about 10,000 lux (that's a unit of light intensity), often for 30 minutes or so a day, Dr. Lewy says. Ten thousand lux is about 20 times brighter than regular indoor lights.
Light boxes should use fluorescent lights. Exposure to full-spectrum lights can cause cataracts and other problems, Dr. Lewy says.
Some people who suffer from SAD benefit from antidepressant medication. Doctors often prescribe selective serotonin reuptake inhibitor (SSRI) drugs such as Prozac, says Dr. Lewy. If you're feeling depressed, it's always a good idea to consult a doctor.