Thomas Edison invented the light bulb, we switched it on, and our bodies’ internal clocks switched off.


Well, not off, exactly, but they got messed up: We started sleeping when it’s light and staying up when it's dark. But that's just not natural, and our bodies know it — and often show it: Winter makes many of us unusually depressed.


It’s called Seasonal Affective Disorder, or SAD, also known as winter blues, and it's very common — and very treatable.


Seasonal Affective Disorder affects more than 10 million Americans, and about 75 percent of them are women, according to studies by Mayo Clinic, the Oregon Health Sciences University and other researchers. Geography (actually, latitude) also plays a big role in who suffers from it; up to 10 percent of all New Englanders are likely to be affected, but only 2 percent of Floridians and Southern Californians are.


For insight on what remedies can help with symptoms of SAD, I talked to Boulder, Colo., psychiatrist Mark Leifeste, M.D., and to four people who experience this condition every winter. If shorter days and fading light make you want to curl up and hibernate until the tulips poke through in March, start with this guide for help.


1. See a doctor to assess your symptoms

A professional can help you determine whether you have Seasonal Affective Disorder and give you several treatment and coping options. You'll likely start by asking you to track your mood swings in a journal.


"You have to look at the big-picture observations through the years," says Leifeste. "I use a calendar that lets my patients chart their moods over a period of three years, or they can fill it in retroactively. Then they might be able to link their mood swings to certain times of the year, like 'It's always around my son's birthday' or 'I notice it around Thanksgiving every year.'"


Besides depression and loss of energy, Seasonal Affective Disorder symptoms include anxiety, social withdrawal, oversleeping, appetite changes and weight gain. Because SAD is a type of depression, it can often be successfully managed by common antidepressants, Leifeste says, but there are a host of nondrug options you can try first.


Of course, if your depression is severe — like if it negatively impacts your daily routine, or you have feelings of hopelessness — see a doctor right away, because it could be something else. "If it's hurting your work performance, relationships, or other abilities to function and cope, get help immediately," Leifeste says.


2. Get outside on sunny days

Don't let colder weather chase you inside; it's what parkas and mittens were made for. Take a walk around the block, eat lunch at the park or simply sit on a bench and relax, advises Mayo Clinic.


Staying active is the key for Shannon Pinkston, who recently moved from Colorado to Missoula, Mont.


"My exercise routine definitely helps with my mood-related issues in the winter," she says. "I keep doing what I do all year; I run outside for a while. Then I can go indoors for additional exercise if I get too cold."


Peter Gowan, who grew up on Long Island and now lives in Colorado, agrees. "I spent every single day of every summer in the sun, until I was 25," he says. "Then for several years I worked in a job that took me to rural parts of Wyoming, North Dakota and other darker, colder states. That's when my seasonal depression started. Now I make time to be outside in the winter."


Take up a new cold-weather sport, like snowshoeing, skiing or ice skating — anything that means you're spending more time outside. A vacation to a sunny locale might also lift your spirits.


Susan Olsen from Rochester, Minn., notices a definite decrease in her energy levels every September when the days start getting shorter. "I always try to schedule a trip to Mexico around January," she says. "Being on a warm and sunny beach always gives me a boost that lasts until spring, when I naturally start to feel better."


3. Try light therapy

Throw open the curtains to let the sunshine stream in as soon as you wake up. Install skylights, if possible, and keep tree branches trimmed so they don't block the sunlight coming through your windows.


Or try indoor light therapy. Also called phototherapy, this approach uses different colors of light to treat different ailments. In 2005, the American Journal of Psychiatry published the findings of a team led by Robert N. Golden, M.D. Golden found that bright light treatment and "dawn simulation" for SAD were statistically as effective as antidepressant drugs in most clinical trials.


Bright light therapy is exposure to specially designed broad-spectrum fluorescent light from 2,500 to 10,000 lux — 10 to 20 times brighter than typical indoor lights. (One lux of light is the approximate equivalent of one candle 3 feet away.) You can get it using a light bath, a small appliance that looks similar to a lighted makeup mirror. Light baths use full-spectrum natural daylight bulbs to simulate sunlight and offer some of its health benefits — without harmful UV rays.



Leifeste says there are many theories about why light therapy works; he believes that it "tricks" the body into thinking it's still summer, preventing the hibernation response. Regardless, more and more health professionals are prescribing bright light therapy for Seasonal Affective Disorder, as well as other conditions, from jet lag to PMS.


"Light therapy is normally used once per day, in the morning, for about 30 minutes at a distance of 3 feet," Leifeste says, but he also cautions that treatment should be individualized for each person with help from a doctor.


You may also want to try blue light therapy, which uses a "narrow" wavelength of the blue light spectrum to naturally help reset your internal clock. Blue light therapy is clinically proven to restore the body’s natural sleep patterns.


4. Do what works for you

To combat SAD, try a variety of therapies, then stick with the ones that work for you. Olsen heads for Mexico. Pinkston exercises. Karen Gilmore moved to the southern hemisphere.


"In the winter," says Gilmore, "my mood is always lower and I have less energy, particularly when I was living in Oregon." She now lives in New Zealand. "It's not as bad here, because it's often sunny in winter and it doesn't get dark as early, but I still prefer spring and summer."


You don't have to go to extremes to find relief, though. In addition to the treatments and approaches listed above, other options suggested by Leifeste, Mayo Clinic, OHSU and the Seasonal Affective Disorder sufferers quoted here include B and D vitamins, omega-3 fatty acids, St. John's Wort, massage, hot baths, psychotherapy, having more sex, afternoon naps, and spending time with friends and family.


Above all, take comfort in three things: you're not a hypochondriac; you're not turning into a hibernating bear; and Edison really did have our best interests in mind.