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Winter Depression Not as Common as Many Think

In a study recently published online in the Journal of Affective Disorders, researchers found that neither time of year nor weather conditions influenced depressive symptoms. However, lead author David Kerr, PhD, an assistant professor of psychological science at Oregon State University, says this study does not negate the existence of clinically diagnosed seasonal affective disorder (SAD) but instead shows that people may be overestimating the impact seasons have on depression in the general population.

“It is clear from prior research that SAD exists,” Kerr says. “But our research suggests that what we often think of as the winter blues does not affect people nearly as much as we may think.”

Kerr says the majority of studies of seasonal depression ask people to look back on their feelings over time. “People are really good at remembering certain events and information,” he says. “But unfortunately, we probably can’t accurately recall the timing of day-to-day emotions and symptoms across decades of our lives. These research methods are a problem.”

So Kerr and his colleagues tried a different approach. They analyzed data from a sample of 556 community participants in Iowa and 206 people in western Oregon. Participants completed self-report measures of depressive symptoms multiple times over a period of years. These data then were compared with local weather conditions, including sunlight intensity, during the time participants completed the reports.

In one study, 92% of Americans reported seasonal changes in mood and behavior, and 27% reported such changes were a problem. Yet the study suggests that people may be overestimating the impact of wintery skies.

“We found a very small effect during the winter months, but it was much more modest than would be expected if seasonal depression were as common as many people think it is,” says Columbia University researcher Jeff Shaman, PhD, a study coauthor and a former Oregon State faculty member. “We were surprised. With a sample of nearly 800 people and very precise measures of the weather, we expected to see a larger effect.”

Kerr believes many people may have overestimated the power of the winter blues for several reasons, including the awareness of SAD, the high prevalence of depression in general, and a legitimate dislike of winter weather.

“We may not have as much fun; we can feel cooped up; and we may be less active in the winter,” Kerr says. “But that’s not the same as long-lasting sadness, hopelessness, and problems with appetite and sleep—real signs of a clinical depression.”

According to Kerr, people who believe they have SAD should seek help. He says clinical trials show cognitive behavior therapy, antidepressant medication, and light-box therapy all can help relieve both depression and SAD.

“Fortunately, there are many effective treatments for depression, whether or not it is seasonal,” he says. “Cognitive behavior therapy stands out because it has been shown to keep SAD from returning the next year.”

— Source: Oregon State University