Burning Question: Is Seasonal Affective Disorder For Real?
Research indicates that, yes, SAD is indeed real. There's ample evidence just outside my office door. Anyone who has lived through an Ohio winter can attest to the oppressive feeling of the dismal gray skies. In fact, during my first year here I began to notice symptoms among students that were consistent with SAD.
Those symptoms include fatigue, extreme sadness, carbohydrate craving, and oversleeping, all of which we also see in depression. And the fact that some Kenyon students were exhibiting these symptoms convinced me that we could conduct fruitful research here, research focusing specifically on cognitive ability, my area of expertise.
First, some background. SAD is a major depressive disorder, no less real than other forms of depression. The difference is that, in the case of SAD, the symptoms are clearly connected to a specific season and are likely to repeat from year to year. It's possible to experience SAD in the summer, but most cases occur between November and March, with the symptoms subsiding by late spring.
Many scientists and physicians hypothesize that SAD may be caused, at least in part, by a lack of sunlight, which could throw off the body's internal clock that regulates sleep and appetite. Some individuals may have a nervous-system vulnerability resulting in even more severe responses to changes in light levels or even temperature. The American Academy of Family Physicians estimates that as many as half a million Americans may suffer from SAD.
Manipulating light exposure indoors with special light-therapy bulbs has been a successful treatment for many people reporting SAD. In fact, Kenyon provides daylight bulbs for the dorms of those students who suffer from SAD. Research indicates, however, that this is not helpful for everyone, a fact suggesting that there are multiple causes of SAD. Social isolation and physical discomfort related to drops in temperature are just a few other potential causes.
As a cognitive psychologist, I am most interested in understanding individual differences in the ability to focus attention and remember information. This ability is impaired in people suffering from major depression, a well-established finding. Previous research has also showed impairments linked to geography and climate--the studies involved military personnel who were moved from an area with a milder climate to a northern region with a colder climate.
These previous findings provided the foundation for a study that I conducted with Brianna Sullivan '04 as part of her senior honors thesis in psychology. Since we had heard students complain about the effects of Gambier winters, we thought we might find individuals who met the qualifications for SAD. In November 2003, when the temperature was a cool 58 degrees and the hours of sunlight dipped to fewer than eight, we assessed ninety-three first- and second-year students for signs of SAD and major depressive disorder, as well as deficits in cognitive function.
We surveyed students about cognitive failures or problems they may have had in their daily activities that would be due to deficits in attention and memory. We found that 28 percent qualified for a SAD diagnosis, and that those individuals had more depressive symptoms than students not qualifying for SAD. I've repeated the study a number of times, and the numbers fluctuate, the lowest percentage being around 7. One trend that emerged clearly: SAD is more common in students moving to the Midwest from sunny southern climates.
Like people with major depression, the SAD sufferers reported cognitive failures at significantly higher rates than people with no identifiable mood disorders. Those qualifying for SAD were easily distracted and had trouble focusing, had working-memory problems, and experienced motor-skill difficulties like tripping, falling, and dropping things, all of which are associated with depression.
Our study not only showed that SAD can compromise everyday functioning. The cognitive failures are also correlated with work-related and automobile accidents. That's one reason why I believe it is very important to identify SAD. This disorder is indeed real and should be taken seriously.
--Tabitha Payne, who joined the faculty in 2002, has studied individual differences in cognitive abilities for the purpose of pilot selection for the United States Air Force. Her current research involves how mood disorders, including SAD, affect cognition.