14 million Americans get the blues in winter - their circadian rhythm goes whack and makes them suffer months-long jet lag

Getting a Grip on the Winter Blues -- by JANE E. BRODY/NY Times

It is that time of year again, when despite the ratcheting up of festivities for the holidays, fully one person in five in the United States ratchets down. The cause is a now well-known but still infrequently treated disorder, winter blues or SAD, for seasonal affective disorder .

There are several remedies to help those affected by SAD escape an affliction that leaves many wanting to climb into bed, put their heads under the covers and not come out until spring. Indeed, some experts refer to SAD as a form of hibernation.

The problem typically starts gradually as the days become shorter in late summer or fall and peaks in midwinter in regions where there may be just 9 or 10 hours of daylight, if that.

For the estimated 14 million severely affected American adults, SAD can send them into a tailspin that makes it difficult if not impossible to fulfill daily responsibilities and derive any joy from life. An additional 33 million people are less severely affected but may experience declines in energy, cheerfulness, creativity or productivity in the dark days of winter.

The most commonly used treatment is exposure for up to several hours a day to high-intensity artificial light, in an effort to simulate the longer days of summer when people with SAD function at top speed.

Jet Lag and Circadian Rhythm

Dr Alfred J. Lewy, a psychiatrist who has been studying the biology behind SAD, describes it as a form of jet lag, a concept he proposed 20 years ago. He recently published experimental evidence that he says attests to the validity of this theory. If true, this would make SAD a disturbance in the circadian rhythm, the 24-hour pattern that normally aligns the sleep-wake cycle with all the other bodily rhythms. Dr. Lewy suggests that with the delayed dawn and shorter days of fall and winter, the rhythms of people afflicted with SAD drift out of phase with the sleep-wake cycle, as if they had traveled across many time zones.

With jet lag, recovery occurs over a matter of days, and the circadian rhythm once again becomes synchronized with day and night. “In people with SAD, this adjustment takes five months,” Dr. Lewy said.

If his theory is substantiated by further research, it may one day be possible to treat SAD with tiny daily doses of time-released melatonin, the substance in the brain that regulates the sleep-wake cycle. Melatonin naturally increases in the evening, causing sleepiness, and falls off as morning approaches. The idea would be to tailor the administration of melatonin in a way that realigns the out-of-sync circadian rhythm in people with SAD, just as tiny doses (much smaller than those typically sold in health-food and drug stores) of melatonin can be used to speed recovery from jet lag.

In his study, conducted with three colleagues at Oregon Health Sciences University, Dr. Lewy identified two types of SAD patients. About two-thirds required morning light or evening melatonin to correct their body clocks. The remainder needed evening light or morning melatonin to put their body rhythms back on track. Currently, there is no commercial source of time-release low-dose melatonin that could be used, with or without light therapy, to help people with SAD.

Current Remedies

Dr. Norman E. Rosenthal, a native of South Africa who discovered his own serious problem with SAD while a resident in psychiatry at the New York State Psychiatric Institute in 1976, has become an expert in diagnosing and treating the problem. His knowledge and experience in helping himself and countless patients afflicted with SAD are summarized in “Winter Blues: Everything You Need to Know to Beat Seasonal Affective Disorder,” whose revised edition the Guilford Press published this year.

Dr. Rosenthal aptly describes SAD as “an energy crisis.” Patients are not depressed in the usual emotional sense, but rather feel as if their batteries have run down.

The symptoms of SAD do mimic those of serious depression. Patients say they have to drag themselves out of bed in the morning, even after 10 hours of sleep, and force themselves to perform necessary chores. They feel leaden and would just as soon not see anybody or do anything. They find it difficult to concentrate and think clearly and quickly.

Sex drive often dwindles markedly but is often replaced by an insatiable appetite for carbohydrates — breads, pasta, potatoes, rice and sweets — that results in weight gain. Many people with SAD have two wardrobes, the one for winter being two sizes larger.

The most common remedy is light therapy. But not just any light. Patients are advised to sit in front of a specially designed light box that emits about 10,000 lux from a fluorescent bulb, most often in the morning for at least 45 minutes. Some patients require hours of light therapy each day to ward off the symptoms of SAD, which may mean having one light box at home and a second at work.

Among commercial sources for these light boxes is the Center for Environmental Therapeutics, which sells them for $200. Its Web site, www.cet.org , is a useful source of information about SAD.

Among other light-enhancing suggestions from Dr. Rosenthal are planning a winter vacation in a sunny climate or relocating to someplace nearer the Equator, where the days are longer in winter. (But, he cautions, first be sure you can tolerate the summer there.)

Helpful Machines and Therapies

For those who remain in northern latitudes, Michael and Jiuan Su Terman of the New York State Psychiatric Institute at Columbia University , who have conducted pioneering studies of SAD remedies, suggest considering a “dawn simulator.” This device gradually turns on a bedroom light every morning while you are still asleep, helping ease SAD symptoms by making the body think that it is experiencing the early sunrises of summer.

This might also help people who do not have SAD but who hate getting up in the morning when it is still dark out.

The Termans have also found another helpful gadget, a negative-ion generator. They showed that sitting in front of a machine that emits negative ions at a high rate for 30 minutes every morning was as effective as sitting in front of a light box for the same time. The generators are available for $165 from the Center for Environmental Therapeutics (Michael Terman is the president of its board). The advantage of this device is that it can be used while sleeping.

A third approach that has proved effective is cognitive behavioral therapy, when used with or without light therapy. Kelly J. Rohan of the Uniformed Services University of the Health Sciences in Bethesda, Md., found that this therapy, a brief form of psychotherapy that helps people change negative thoughts and behaviors, was as effective as light therapy in a study of 23 patients with SAD.

And unlike light therapy used alone, cognitive behavioral therapy helped prevent a relapse of SAD symptoms the next winter.

Dr. Rosenthal also recommends eating a diet relatively high in protein and low in carbohydrates and performing regular physical exercise, which is especially helpful if it is outdoors in the morning or, if indoors, in front of a light box.