When the days get shorter and the wind blows colder, it's easy to feel a little glum. But for some people the darker days can trigger serious depression. As many as half a million Americans are struck each year by seasonal affective disorder, or SAD, a type of depression that comes and goes with the darkest half of the year; another 10 percent to 20 percent of the population experience something just short of it. And though it's not clear why, doctors say women are three times as likely as men to be affected by it.
This isn't the holiday blues. As Dr. Norman Rosenthal, the psychiatrist who wrote the defining medical journal article on the disorder in 1984, explains, the blues are gone in a week or two, but SAD typically starts around Columbus Day and hangs on until about Easter.
Still, the confusion between the two may help explain why, more than 20 years after SAD was first diagnosed, most people with the disorder aren't getting help. Rosenthal said a recent study found that even among subjects who reported having experienced an average of 13 cycles of SAD symptoms, 60 percent had never gotten a diagnosis or treatment. "A lot of these cases still don't get recognized, even though SAD can be very persistent, and some people become disabled by it," Rosenthal said.
Even though it's called SAD, the typical symptoms extend beyond unhappy feelings. As Rosenthal describes it in his book "Winter Blues," SAD not only causes symptoms of depression (feelings of irritability, difficulty concentrating, fatigue, oversleeping, social isolation) but, often, a strong craving for sweet and starchy foods, and the weight gain that inevitably accompanies it. Like people with other forms of serious depression, those with SAD can find it hard to hold down a job or function normally, and some may contemplate suicide.
Rosenthal, now a clinical professor of psychiatry at Georgetown University Medical School, said he experienced some of these symptoms himself when he first moved to the United States from South Africa in the late 1970s, to begin work as a researcher at the National Institute of Mental Health. During his first autumn in Washington, D.C., he couldn't help noticing that as the days got shorter his energy level declined. "I didn't know what hit me," he says now. "I dragged myself through that first winter." Equally surprising, he said, was the change he noticed in the spring. "As the snow melted," he said. "my energy came back."
At the time, groundbreaking work was being done at NIH on light's effect on the brain, and coincidentally Rosenthal met a male patient who complained of severe mood changes that lasted from late fall to spring. That's when Rosenthal had his "Ah-ha!" moment. "I wondered if there were other people like him, and wouldn't it be great to study them," Rosenthal said. He's been doing that ever since.
It's still not understood why women develop SAD at three times the rate of men, but Rosenthal says it may be related to an increase in reproductive hormones. Symptoms tend to first appear in women who suffer from SAD soon after a girl begins to menstruate. While SAD symptoms can reappear winter after winter, they tend to decline or largely disappear in women after menopause. As women age, he said, "the preponderance of SAD becomes more equal between men and women." One theory is that SAD may be somehow related to the seasonal hormonal changes that gear animals to reproduce during the time of year when their offspring are most likely to survive. "Light is believed to play a role in evolution as a mechanism for controlling reproductive function," Rosenthal said. "It may be that in certain people a primitive mechanism is unleashed that is not overridden by today's artificial light."
There are also indications that the condition is more common in some ethnic and racial groups than others. "Icelandic people tend to have much lower levels of it," Rosenthal said. "The same is true of Asians, including the Japanese and Chinese." It's possible that some groups adapted better than others, he said, but it may also be that those who were made the most miserable by long, dark days were motivated to move to sunnier climates.
Like other forms of depression, SAD runs the gamut from mild to severe cases, but Rosenthal says no one has to wait until the disorder becomes debilitating to take action. Some people need a combination of treatments, like antidepressants and cognitive behavior therapy, to feel better. But alternatives, like increased exposure to light, more exercise, stress-reduction strategies and changes in diet (less carbs, more protein, à la the South Beach or Atkins diets) can also make a big difference. Specially designed "light boxes" that simulate the brightness of the outdoors on a sunny day can help, as can light visors that can be worn like a hat. Check with a clinician to determine the appropriate "dose" and timing of light therapy so that symptoms decrease but the therapy doesn't affect your ability to fall asleep at night. Traveling to sunnier climes for the winter also helps, Rosenthal said. (Tanning beds, however, are not recommended.)
Rosenthal said he has learned to reduce his own symptoms by sticking to a disciplined regime from October to April. He has a light box that turns itself on each morning and gradually brightens, until it floods his bedroom with simulated daylight. He has also become a big fan of brisk morning walks. Not only is it a good way to get vigorous exercise, but even on a gloomy day the outdoors is much brighter (and mood-lifting) than an artificially lit interior. Over time, he says, he has learned to appreciate the change of season. "I even enjoy ice storms and dark, dreary days," he said. Maybe for him, but a prescription for a month in the Caribbean sounds better to us.