Yale Researcher Sheds Light On Winter Depression, Studies Could Help Patients With Seasonal Affective Disorder

Research by Dan A. Oren, M.D., associate professor of psychiatry at Yale University School of Medicine and president-elect of the Society for Light Treatment and Biological Rhythms in Colorado, could help alleviate SAD symptoms that include fatigue, sadness, weight gain and sleep problems.

"My studies explore how light works to treat SAD, and I am looking at ways to define the process by which red blood cells may absorb light energy and have antidepressant effects," says Dr. Oren, chief of affective disorders research at the VA Connecticut Healthcare System in West Haven, Conn. "For many years, people were told that they were imagining winter depression, but it is now being looked at as a very real form of depression."

According to Dr. Oren, SAD affects up to 10 percent of people in the northern United States and women are more vulnerable to the disorder than men. Unlike other forms of depression, the disorder appears when winter arrives, leaving most sufferers feeling sluggish and weak, with an inexplicable craving for carbohydrates. Treatment studies of SAD have centered on the effects of light on mood.

Scientists know that in humans as in plants, light may play a central role in behavior and that there are biological clocks within all forms of life. Studies show that a strong dose of light from a specialized light unit can often melt winter depression away, but the reasons why light is an effective treatment remain a mystery.

Some researchers speculate that the shorter and darker days of winter slow down the brain's biological clock, altering the balance of neurotransmitters and leaving some people feeling lethargic. Dr. Oren's research at the Center for Light and Psychiatry at Yale School of Medicine looks at how light impacts hemoglobin in the blood and its association with depression. He compares the blood of SAD patients with the blood of healthy individuals in an attempt to come up with more clues to understanding the disorder.

"Blood absorbs light energy from the sun," proposes Dr. Oren, whose research is funded by a career development award from the U.S. Department of Veterans Affairs. "The blood can then regulate our biological clocks, our physiology and our behavior. My theory is that in people who get SAD, the blood isn't absorbing enough light."

Previous research has shown that light therapy on the eyes can alter the biological clock, but a recent study by researchers at Cornell University School of Medicine, shows that light can affect the body clock through the skin as well. Dr. Oren's comments on the skin study appeared in the Jan. 16 issue of the journal Science.

"This new work begins to provide empirical evidence to support my theory that blood is a messenger for light and that blood absorbs light through the eyes and in the skin," says Dr. Oren. "This also suggests that SAD might be a disorder of the blood rather than a brain disorder."

As part of his study, Dr. Oren is offering free light therapy treatment at the Mood Disorders Research Clinic, located at the West Haven campus of the VA Connecticut Healthcare System. For more information or to participate in the study, please call (203) 937-4862.