A SAD Time of Year

Seasonal affective disorder affects up to 25 million Americans. As the days get shorter, many people begin to feel depressed. They become irritable, lose energy, experience anxiety, have difficulty concentrating or even getting out of bed in the morning. This type of winter depression has probably been around for centuries. In the 1980's, psychiatrists named it Seasonal Affective Disorder, or SAD.

Linked to a decrease in daylight hours and more prevalent in higher latitudes, the winter doldrums vary in severity, according to Dr. Levitan. "About 30 to 50 percent of people will tell you their moods change, that they sleep more or have less energy," he said. They may have a mild case of "winter blues."

Another 10 to 15 percent of the population have more serious symptoms, according to Dr. Levitan. Feeling a general malaise, they have trouble getting things done. They often sleep more, eat more and have a lower energy level. Basically, though, they are able to function.

For people with full-blown SAD, about two to three percent of the population, the disorder can be life-shattering. Seriously depressed, they withdraw from social activities. "As symptoms worsen, they often lose their job or an important relationship, or drop out of school because they can't function," says Dr. Levitan. "In the most severe cases, people may commit suicide." A hallmark of the disorder is a voracious appetite. People crave carbohydrates and often gain 10 to 20 pounds. When Spring comes around, they begin to feel better. As the days get longer, their mood improves, they have renewed energy and may lose the weight they gained.

Three out of four sufferers are women, but even children are not immune. According to a report in the Journal of the American Academy of Child and Adolescent Psychiatry, more than 1 million children may be afflicted.

The tragedy is that more than half of those affected don't seek help, according to Dr. Levitan. "It's extremely important for people to get professional help if they're having trouble functioning, and especially if they're having suicidal thoughts," he says.

NARSAD Researcher Sheds New Light on Seasonal Affective Disorder

In the winter months, seasonal depression is a serious concern, but exciting research by a NARSAD-funded scientist is shedding new light on seasonal affective disorder, or SAD. Articles in two New York area newspapers, the Daily News and Newsday, highlighted the findings of Robert Levitan, M.D., Research Head of the Depression Clinic at the Center for Addiction and Mental Health at the University of Toronto. Dr. Levitan, an assistant professor of psychiatry who received a NARSAD Young Investigator Award last year, is delving into the genetic mechanisms that may trigger SAD.

Dr. Levitan hypothesized that the brain chemical serotonin plays an important role in both SAD and another illness that occurs predominantly in women--bulimia nervosa (BN). Both disorders are characterized by an increased food intake and depressed mood. Thanks to recent developments in neurobiology, scientists are able to analyze the genetic underpinnings of the serotonin system. So far, Dr. Levitan and his colleagues have found preliminary evidence of a genetic predisposition to SAD and BN.

The researchers are studying three components of the serotonin system involved in satiety, production of serotonin and response to drugs that affect serotonin levels such as Prozac in female patients. To date, Dr. Levitan has followed 90 women diagnosed with SAD, 127 with BN, three patients who have both disorders and 101 control subjects. Dr. Levitan and his colleagues found that women with SAD or BN were more likely to have a particular polymorphism, or variation, in a serotonin gene called tryptophan hydroxylase (TPH).

Dr. Levitan notes that his research is in its early stages, but future studies could have a significant impact on the treatment of these two common disorders that cause significant disability and can even be fatal. "Identification of at-risk individuals could lead to preventive strategies implemented at an early age and to the development of new highly effective medications targeting serotonin," he said. Dr. Levitan has presented the preliminary data at several international meetings, with nine peer-reviewed abstracts accepted to date. He will continue to recruit study participants and take a closer look at the genetic link.