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SAD Season at its Peak

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Duke Health News 919-660-1306

This time of year is the peak of "SAD season." Seasonal Affective Disorder, is a form of depression associated with seasonal variation in light.

"We don't know exactly what causes it," says John Beyer, M.D., assistant clinical professor of psychiatry at Duke University Medical Center. "It appears that the decreased amount of light in certain susceptible people causes the onset of depressive symptoms. This usually occurs in late fall or early winter, most commonly in the January to February period, and then usually resolves by spring or early summer."

About 2 percent of Americans suffer from SAD, says Beyer, who directs Duke's Mood and Anxiety Clinic. "It's possible that location, where one lives on the Earth and how much exposure to sunlight they get may affect how common SAD is in different areas. Also, certain northern tribes appear to have adapted to sunlight changes, so that they actually have decreased incidence of Seasonal Affective Disorder.

"Women have the condition at about twice the rate of men, which is similar to depression in general. Children can be affected, too. The most common times for people to have this condition is in adolescence and in their reproductive years, their 20s and 30s. As we age into our 40s and 50s, it becomes less common."

Beyer says SAD symptoms are much like those of other forms of depression -- depressed mood, a decrease in motivation or enjoyment of activity, problems with sleep and with appetite and a general feeling of being "down." There are, however, two interesting exceptions.

"During the winter people with Seasonal Affective Disorder tend to have increased sleep, kind of like bears hibernating," he explained. "Also, instead of having decreased appetite and weight loss, people with SAD tend to gain weight or have increased appetite, especially for carbohydrates, sweets and sugars."

Beyer says effective treatments are available for most cases.

"One treatment that's widely prescribed is the use of phototherapy, usually in the form of lightboxes," he says. "These are small boxes with fluorescent lights inside. They aren't the regular fluorescents like we have above us, but are extremely bright lights, somewhere between 2,000 and 10,000 lux.

"Additionally, we encourage people to go outside and be exposed to sunlight, since that will accomplish the same thing. Light therapy is effective in about 65 percent of cases. The exposure for about 30 minutes to two hours significantly reduces the incidence of Seasonal Affective Disorder for people who have this common problem."

For patients who don't respond to phototherapy, Beyer says antidepressants can help. "Serotonergic reuptake inhibitors, or SSRIs, such as Zoloft and Prozac, can also be useful in treating this condition," he said.

Beyer says Seasonal Affective Disorder can cause considerable distress, but that effective treatments can help control the condition during difficult times of the year. "The good news is that we can identify it," he says. "The better news is that we can treat it."

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