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AS winter gives way to spring and light comes back into the world do you find yourself with more energy, feeling better? Could you have Seasonal Affactive Disorder (SAD)?

In his narrative of a voyage to Antarctica, first published in 1900, Dr. Frederick A. Cook chronicled the ordeals of a high-latitude winter: "The winter and darkness have slowly but steadily settled over us. By such easy stages has the light departed that we have not, until now, appreciated the awful effect."

Though the conditions experienced by Dr. Cook and his colleagues were undoubtedly more extreme than most of us will ever experience, the depiction of winter gloom is familiar to many. “If you ask people if they generally feel better or worse at one time of year than another,” says Janis Louise Anderson, PhD, assistant professor of psychology at Brigham and Women’s Hospital in Boston, “up to 25 percent of people in the northern latitudes say that they feel worse in the winter.”

For some of these people, seasonal mood changes may be mild, reflecting a simple preference for one season over another rather than a disorder. Others, however, may find that their daily lives are profoundly affected during certain times of year. Seasonal affective disorder (SAD) “is a depression that comes back on a predictable basis every year and goes away on a predictable basis every year,” explains Dr. Anderson. “It can reach a level of major depression.”

Symptoms of depression include persistent sadness, loss of pleasure in usual activities, difficulty concentrating, feelings of guilt or hopelessness, sleep problems, and appetite changes. For someone with SAD, symptoms typically appear in the fall and persist through the winter months. If untreated, symptoms generally go away sometime in the spring.

SAD tends to be more common in women, at higher latitudes (regions farther from the equator), and among people with a family history of mood disorders or alcoholism. The condition can occur at any age, but people most often begin to notice symptoms in their early twenties.

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Though the biological basis for the condition is still not well understood, changes in length of day and exposure to light appear to be factors. As a result, light therapy plays an important role in treatment for many patients. “There are a couple different kinds of light treatment,” explains Dr. Anderson. “The standard one is to acquire a device that has fluorescent tubes that put out a white light that’s pretty bright.” Use of about 10,000 lux (lux is a measure of light intensity) for half an hour each morning provides relief to many patients. Devices called “dawn simulators” are another approach. These devices are used to gradually increase the amount of light in a bedroom before someone wakes up. “The dawn simulator has less research,” notes Dr. Anderson, “but it’s looked successful in the trials that have been done.”

The need for special (and safe) light equipment is important for patients to understand. “Sometimes people just want to put brighter bulbs in their rooms,” says Dr. Anderson. “That’s really just a waste of money because you cannot get the level of brightness that you need from ordinary light bulbs.” In addition, because light treatment devices are not regulated by the US Food and Drug Administration, it’s important for patients to do their homework and talk with their healthcare provider before buying a light box. The light box needs to provide a type and an intensity of light that’s likely to be effective against SAD while filtering out potentially harmful ultraviolet light. It’s also important to talk with your healthcare provider about your other health conditions and medications (including herbal remedies such as Saint-John’s-wort and dietary supplements); some conditions and medications can increase photosensitivity and make light treatment risky.

Other treatments that may be used for SAD (either alone or in combination with light therapy) include antidepressant medications and cognitive behavioral therapy. Simply getting outside during daylight hours may also provide a boost to your mood. “In the winter the sun is still very potent and still many times brighter than indoor light,” says Dr. Anderson. “The trick is to get out in it.”

In short, the message for SAD is much the same as for nonseasonal depression: Seek care. Help is available.


  1. Cook FA. Through the First Antarctic Night, 1898-1899: A Narrative of the Voyage of the Belgica among Newly Discovered Lands and Over an Unknown Sea about the South Pole.New York: Doubleday and McClure; 1900.
  2. Magnússon A, Stefánsson JG. Prevalence of seasonal affective disorder in Iceland. Archives of General Psychiatry. 1993;50(12):941-46.
  3. Axelsson J, Stefánsson JG, Magnússon A, Sigvaldason H, Karlsson MM. Seasonal affective disorders: relevance of Icelandic and Icelandic-Canadian evidence to etiologic hypotheses Canadian Journal of Psychiatry. 2002;47(2):153-58.</li.

Hibernation Is Not the Answer

Asked about how to manage mild seasonal mood changes (those that don’t meet the criteria for a SAD diagnosis), Dr. Anderson responds, “It’s certainly true that light can be helpful there too, so it’s not necessary to have a clinical depression to feel some benefits from having more light exposure. Also, when you’re physically active it helps your mood, so getting outdoors and taking a walk in the morning light would be a great thing for people. Sometimes people say, ‘Oh, it’s winter; it’s the time of hibernation. I’m just going to lie on the couch.’ That’s bad because we are not bears, and it’s not good for us to just lie around in the winter.”

Iceland in January: Cold, Dark, and…Happy?

To illustrate the role that genetic factors may play in SAD, Dr. Anderson points to Iceland, a high-latitude country with an unusually low incidence of SAD. Iceland is located just below the Arctic Circle, and the shortest winter days have only four hours of sunlight. Nevertheless, SAD appears to be less common in Iceland than in the United States.2This lower risk of SAD even seems to apply to people of Icelandic descent who live in other countries.3 Researchers have speculated that Icelanders may be genetically adapted to winter darkness.