Winter light can mean discontent, even depression

For millions of Americans, the coming of winter means depression as dark as a December evening.

Dr. Norman E. Rosenthal knows this well. A South African native, Rosenthal noticed a change in himself soon after arriving in New York to complete his psychiatric residency. With the change of seasons he grew tired, irritable, and easily overwhelmed. And like many who suffer these seasonal symptoms, he thought he was alone.

But toward the end of his residency, at the National Institute of Mental Health, he met a man who suffered in much the same way. He decided to study the condition. Testing his theory that reduced light may be to blame, Rosenthal subjected the man to a series of intensive light sessions over a period of days.

Three days later, he felt dramatically better. And when the results of his study were published, Rosenthal was shocked by the response.

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“I thought I was dealing with a very rare syndrome,” said Rosenthal, a professor at Georgetown University. “To our amazement, we got thousands of responses.”

From that work in the mid 1980s, Rosenthal discovered a disorder now believed to afflict some 10 million Americans: Seasonal Affective Disorder, or SAD.

Researchers also believe that stress can make the condition worse. That does not mean, however, that everyone who feels a little bit down during the winter months has it. Though the disorder has varying degrees of severity — from a slight loss of energy to the complete inability to function normally — it is a real clinical condition, doctors say.

“There’s really a profound difference between the blues in the winter and SAD,” said Jon Brett, a Ph.D. clinical psychologist at Newport Hospital.

The difference is that SAD patients suffer from a chemical imbalance believed to be caused by a reduction of light passing through the eyes. One theory is that the reduced light triggers the sufferer to produce less of a neurotransmitter called serotonin, which researchers believe affects moods, motivation, and a variety of other functions in a way that is not yet fully understood.

Some researchers also believe that the hormone melatonin — which in animals controls the ability to differentiate between long and short nights and between different seasons — plays a role, as the SAD sufferer begins to produce too much of it. This would explain why patients tend to sleep too much. Some even suggest that an analogy can be drawn between SAD and hibernation. Rosenthal, however, notes that that idea, while useful as an analogy, falls short as a model because the biological correlation between the two is not as close as that idea would suggest.

Still, the basic tendency to conserve energy appears to be the same. SAD sufferers tend to crave for carbohydrates. Their circadian rhythm has been altered, meaning they sleep too much at night and feel tired during the day. Loss of creativity, motivation, and libido have also been reported as symptoms.

But while it is clear that millions of people suffer with the change of season, what is not yet clear is whether SAD is a distinct disorder, or if it is merely the worsening of a mood disorder that already exists, said Dr. Lawrence H. Price, chief of the mood disorders program and director of research at Butler Hospital in Providence. That, he said, may take years to determine.

“We’re still in the process of trying to discover if it’s a separate disorder or not,” Price said. “The status of that issue is unresolved.” Though experts say it has always been known intuitively that seasons affect moods, most of the knowledge of the disorder has come in the last five to 10 years. They also note that much more research is needed. For example, Price said recent studies indicate many people with mood disorders feel differently at different times of the year. He also added that some research suggests that the condition may not be permanent.

“The studies don’t show clearly that it is sustained indefinitely,” he said.

For those who do suffer now, however, treatment is available. Researchers, in fact, say one of the best treatments is simply understanding that you have a clinical condition. A large proportion of sufferers — doctors say it is difficult to say how many — think their condition is nothing more than winter doldrums.

The principal treatment for a relatively mild condition is light therapy. The patient sits near a high-intensity light for a given period, usually 15 to 30 minutes in the morning. Numerous companies produce such lamps designed for SAD sufferers. A local example is Verilux Inc. in Stamford, Conn., which makes the Happylite, which retails for $399 and can be bought via catalog. Nicholas Harmon, president and chief executive officer of the company, said some health insurers now reimburse patients for the cost of light therapy.

The light is believed to stimulate the production of serotonin, and mood improves.

“You’re trying to trick the brain into producing serotonin and not producing melatonin,” Harmon said.

For those with more serious conditions, a doctor may prescribe anti-depressants. But doctors also encourage suffers to attack the disorder on their own. Just getting outside, exercising, eating less, and being more active will help, they say.

Rosenthal, who has written a book on SAD called “Winter Blues,” said he employs these techniques, which he suggests in his book. Cross-country skiing, in which sunlight reflects off the snow, is a particularly good exercise, he said.

“Light and exercise is a very powerful combination,” he said.

Most patients are women, according to Rosenthal, who said the ratio of women to men sufferers in four to one. Of those women, most are of reproductive age. Males of any age may have SAD, he said.

Predictably, most SAD suffers live in the northern hemisphere. Doctors, therefore, say vacationing in the south can be helpful.

“One of the cures,” Brett noted, “is to move to Miami.”

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