I remember growing up that when the days got short, were overcast, or just really foggy, for a while my mom always got pretty melancholy. At age eight, not being a licensed psychiatrist, I didn’t know if this was just a sort of “Rainy Days and Mondays” kind of thing or a serious—i.e. in the book—disorder, but later when I heard about “seasonal affective disorder” it was a low-key “eureka” moment. Although I was pleased to know my mom was pretty average in this regard, it came with a twinge of guilt—what if I‘d gotten my mom some sort of full-spectrum lamp for Christmas instead of macaroni-based jewelry and corrosive perfume?
A 1989 study reported that up to 92 percent of adults noticed some effect on their mood based on season, with young women tending to show the greatest despondency. But new research suggests the whole seasonal affective disorder thing, while it is a thing, may be a bit overblown.
Part of the issue, according to David Kerr of Oregon State University, who was the lead author of a paper appearing in the Journal of Affective Disorders, is that past studies relied on self-reporting and recollection. “People are really good at remembering certain events and information,” Kerr was quoted in a release from OSU. “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 his team piggybacked on two long-term longitudinal studies, the 30-year Oregon Youth Study and the 23-year Family Transitions Project, to compare actual markers of mood logged several times each year and then compare those findings to the length of the day, amount of sunshine, and the weather. On average, the participants indeed were sadder on shorter days, but “this trend was of modest magnitude and of limited clinical significance,” Kerr and his colleagues wrote.
“We were surprised,” co-author Jeff Shaman of Columbia University was quoted. “With a sample of nearly 800 people and very precise measures of the weather, we expected to see a larger effect.”
While it runs counter to many of the earlier studies, this new research also backs up a 2004 European study (it included sunny Spain and taciturn Finland) that also questioned the prevalence of SAD. That this new study only looked at people from Oregon and Iowa is one of the limitations its authors cite, since SAD is more common in the highest latitudes.
In fact, the authors go to some pains to say they still believe in SAD and specifically recommend cognitive behavioral therapy for its promise. But its pop psychology uses—e.g. diagnosing my mom’s depression—are probably best left alone. The blues in winter can have many causes, from holiday pressures and being cooped up to awareness that there’s this malady known as SAD. “But that’s not the same,” Kerr said, “as long-lasting sadness, hopelessness, and problems with appetite and sleep—real signs of a clinical depression.”