Lighten Your Mood

After too many gray days, your mood can start to match the sky: an expanse of blah, with the occasional squall. Well, crawl out from under the covers. New research shows that a few simple changes can lift your spirits--and your energy.

If the short, dimly lit days of winter grind you down into a gloomy state of mind, and you find yourself munching junk food and hunkering down to doze glumly in front of the TV instead of heading out to have fun, you probably have the winter blues. You're not alone. By some estimates, as many as 1 in 4 people in northerly climes find that their emotional temperatures drop as the days shorten. Perhaps 1 in 20 develop full-blown depression, or "seasonal affective disorder"--aptly abbreviated SAD.

If you're SAD, you may find it cold comfort, but your distress probably indicates you're more closely attuned to nature's rhythms than are people who sail through the seasons unperturbed, says Thomas Wehr, M.D., chief of the Section on Biological Rhythms at the National Institute of Mental Health, in Bethesda, Maryland. After all, many of our animal kin sleep more, move around less, and generally lie about all winter. "I guess if they could talk, they would say they just didn't feel like doing much," says Dr. Wehr.

In nature, all mammals respond to the passing seasons with changes in secretion of melatonin. This hormone has become a remedy for jet lag, but its real role is to help set the body clock by signaling the onset of night. The brain begins producing it around dusk and quits around dawn. Or at least it used to--nowadays, with electricity to brighten long winter nights and window shades to darken summer mornings, most of us pump out melatonin for about 10 hours per night, in winter or summer.

People who suffer from a seasonal sag in spirits, however, seem to be less sensitive to the flip of a light switch. Dr. Wehr found that volunteers with the winter blues produced more melatonin in winter than did those with normal moods.

But SAD isn't as simple as "more melatonin = winter depression." When Dr. Wehr brought a group of volunteers into his sleep laboratory for 14 hours of darkness each night, everyone's period of melatonin secretion lengthened to match the long nights--but only one got sucked into the blahs as a result. Dr. Wehr suspects that's because SAD is a two-part ailment: The ebb and flow of melatonin is a factor, but you also need to be prone to depression in some way. Other researchers have shown that SAD tends to run in families.

There's another possibility. Maybe SAD arises not because we can't ignore the seasons, but because we do ignore them. After all, most of us set our alarm clocks for the same time, no matter what the season. The problem is, we have an internal clock, too, with many of our biological rhythms running in a roughly 24-hour cycle--the ups and downs of body temperature, for instance, and the release of many hormones. Each day, that internal clock resets itself slightly, synchronizing itself with the dawn's earliest light. Yet in wintertime, we generally drag ourselves out of bed before dawn. The result: Our sleep-wake cycle drifts out of sync with our internal clock. "It's like having jet lag for five months every winter," says Al Lewy, M.D., Ph.D., a psychiatrist at the Oregon Health and Science University, in Portland.

How Light Can Help
Sure enough, in an experiment where Dr. Lewy treated the winter blues by giving melatonin pills to sufferers in an effort to shift their internal clocks to match their actual wake-up times, most people got better. If you want to try this yourself, you can take up to ½ milligram of melatonin in the afternoon, Dr. Lewy says. Just be careful about afternoon driving, as the hormone may make you sleepy.

"We maintain an 11 P.M. to 6 A.M. sleep-wake cycle to keep our jobs," says Michael Terman, Ph.D., who directs the winter-depression program at Columbia-Presbyterian Medical Center, in New York City. "If we allowed our sleep patterns and work obligations to float with the seasons, we might see less depression."

The winter blues, like vampires, tend to fade away when exposed to light. For several years now, the best therapy for SAD has been to sit in bright light for a half hour or so each morning. You can now buy specially designed light boxes that deliver the proper intensity (at least 10,000 lux of white light), and some are even color-balanced to minimize glare.

But for a sizable minority of people, the therapy doesn't work. It turns out that timing is everything, say researchers, who are only just learning how to get the rhythm right. The key, says Dr. Terman, is to deliver the light 7 1/2 to 9 1/2 hours after the onset of internal night--that is, the time when your body begins secreting melatonin, the nighttime hormone. But internal night can vary from person to person by as much as 6 hours, so someone who's up with the larks may need her dose of light much earlier than a night owl would.

People who get the timing right have an 80 percent chance of beating the blues. "That's spectacularly high for any antidepressant intervention," says Dr. Terman. In contrast, those who miss the crucial window might just as well have taken a placebo. To help hit the target, Dr. Terman has developed a simple questionnaire that can quantify just how much of an owl or lark you are and pinpoint the best time for you to turn on the light box. (His Automated Morningness-Eveningness Calculator is available at the Center for Environmental Therapeutics Web site, www.cet.org; you can also find a range of light boxes there.)

Unfortunately, the ideal time for light-box treatment comes very early in the morning. The "moderate lark" should start light therapy around 5 A.M., for example, which is probably a good deal earlier than even a lark would like--particularly one in the grip of the winter blues. SAD causes people to sleep more than normal, so they tend to have a terrible time rolling out of bed early to shine a bright light in their face.

Fortunately, a better way of treating SAD may be just around the corner. Dr. Terman and a few other researchers are investigating a simulated dawn, in which a computer-controlled lamp gradually brightens to mimic the first light of predawn. "The idea is to create springtime sunrise in the darkened bedroom when it's still completely dark outside," says Dr. Terman. Our bodies are extremely sensitive to daybreak; in the initial experiments, these glimmers banished depression just as effectively as bright light. If further research bears out the promise, there may soon be no need to get up at an ungodly hour or take time out of a rushed morning schedule. Instead, you may be able to sleep right through the simulated dawn and wake up feeling fine.

Eat Fat, Feel Better
Here's a heretical notion: If you're feeling down, you may be suffering from a shortage of ... fat.

No one is saying that our modern diet is too lean. But researchers are increasingly convinced that our diet is far too light on a specific kind of fat, called omega-3 fatty acid--the kind of fat typically found in fish. The shortfall, they say, may be bad news for moods. "Omega-3 fatty acids play a crucial role in brain function," says Andrew Stoll, M.D., who directs the Psychopharmacology Research Laboratory at Harvard Medical School-McLean Hospital.

What is it about fish that goes to your head? Omega-3 fatty acid is one of the most abundant fats in gray matter, and it tends to concentrate in cell membranes. When omega-3s aren't available, other fats take their place, most notably one known as omega-6 fatty acid. But a deficit of omega-3s, Dr. Stoll says, may make the cell walls just a little stiffer, disrupting the ebb and flow of crucial chemicals such as serotonin, which plays a role in controlling mood.

In our modern diets, we typically consume up to 20 times more omega-6s than omega-3s. Taking fish-oil capsules is one way to balance the ratio. Here are a few things to consider before you try it:

• If you suffer from depression, talk to your doctor before popping fish-oil pills. And don't toss away any prescribed mood medicine: Studies so far have looked only at fish-oil capsules taken with standard mood stabilizers or antidepressant medications. It's also wise to check with your doctor if you're taking a blood-thinning drug, since omega-3 fatty acids also act as mild anticoagulants.

• Omega-3 fatty acids come in three forms: alpha-linolenic oil, eicosapentanoic acid (EPA), and docosahexanoic acid (DHA). EPA seems to be the key player when it comes to easing depression, Dr. Stoll says, so he recommends brands that contain more EPA than DHA (most brands show the percentage of each on the label). Look for supplements that have an omega-3 concentration of 50 percent or higher.

• The capsules shouldn't smell or taste fishy; if they do, the oil may have begun to turn rancid.

• How much to take? Researchers aren't yet sure, but studies use doses that range from 1 to 4 grams.

• Not everyone is keen on capsules, however. Andrew Well, M.D., recommends eating fish instead, out of concern that some capsules may contain high levels of environmental toxins such as cancer-causing dioxins. Dr. Stoll, though, argues that fish-oil capsules made by leading supplement manufacturers are safe and less likely to contain contaminants than fish itself. Capsules may also be the only practical way for someone with depression to get sufficient omega-3s to lift the dark mood, they both agree. If you need to take supplements, you can play it safe by purchasing brands that state on the label that they've been distilled to remove contaminants.

--Peter Jaret
Seasonal Signs

Although SAD may be the most publicized way our bodies respond to the changing seasons, it is by no means the only reaction. Here's a sampling of some others:

• Most of us feel our spirits brighten when spring rolls around, at least for a while. But a sizable portion of SAD sufferers--perhaps as much as 25 percent--become so excessively upbeat that their good mood verges on mild mania.

• Many people with bulimia are more prone to binges during winter months--and there's some evidence that early-morning light therapy can ease their symptoms, too. Most likely this link has to do with seasonal variations in levels of the brain chemical serotonin. A wintertime decline in serotonin can leave people feeling both depressed and hungry.

• Birth records from before the industrial revolution show that more children were conceived during spring and fall than in summer and winter. These peaks have declined somewhat since the advent of artificial lighting, but even today, in vitro fertilization is more likely to succeed in springtime, when women and men produce more sex hormones than at other times of the year.

• Breast, prostate, and colon cancer are more common in people who live at high latitudes, and the reason may be their paltry exposure to sunlight. During the long, dark winters, they don't make much vitamin D because its manufacture is triggered by the ultraviolet radiation in sunlight. The evidence isn't conclusive, but the epidemiological evidence is suggestive. So are lab studies: In test-tube experiments, for instance, vitamin D inhibits the growth of breast-cancer cells and prevents prostate-cancer cells from metastasizing.

• Most people sleep more during the winter, even if they're not depressed. But for a few unlucky people, that urge hits like a sledgehammer, which can cause serious social problems. "If you cannot wake up until 11:30 in the morning, you're not going to be able to maintain your 9-to-5 job," says Dr. Terman. Early-morning light therapy may help this problem, too.

Exercise Your Demons
Forget those old clichés--it looks like you really can run away from your troubles. A number of studies suggest that exercise can lift your spirits; a workout may even help scrape you up off the floor if you suffer from serious depression.

One particularly impressive study from Duke University looked at patients with major depression who were put on a workout program (30 minutes of brisk walking, jogging, or pedalling on an exercise bike, three times a week), an antidepressant regimen, or a combination of the two. After four months, exercise provided just as much relief as the heavy-duty drugs. And activity was actually better than drugs at preventing a relapse.

Some of the mood boost may be due to the fact that exercisers worked out together, says researcher James Blumenthal, Ph.D., so they got an extra dose of social support. But Dr. Blumenthal suspects that huffing and puffing has a direct effect on the brain. So if you want to double the benefits of regular exercise, jog over to a friend's house.

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By Bob Holmes

Bob Holmes is a correspondent for New Scientist magazine.

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