SAD news: Seasonal Affective Disorder may not be real
SEATTLE — Getting up in the dark, going to work in the rain, coming home in the dark. It’s a routine we all trudge through in our winter months here in the Pacific Northwest. Seattle only gets 8 hours and 25 minutes of daylight in our darkest time of year, which coincides with our rainiest part of the calendar. But, if you think you get down and depressed in our dark Northwest winters, it might just be all in your head. New research from Auburn University says Seasonal Affective Disorder or SAD doesn’t really exist. Their study published recently in the journal for Association for Psychological Science find no link between major depression and latitude, season or sunlight.
Seasonal Affective Disorder got a lot of attention in the 1990s. It even made it into the Diagnostic and Statistical Manual of Mental Disorders, a bible of sorts for those in the psychological circles that dates back to the 1880s. But, the Auburn researchers say, “the idea of seasonal depression may be strongly rooted in folk psychology, but it is not supported by objective data.” The study was based on surveys of a cross-section of U.S. adults who completed the Patient Health Questionnaire- 8 Depression Scale. A link to the questionnaire is here: http://patienteducation.stanford.edu/research/phq.pdf The quiz is a multiple choice self-reporting inventory that is used as a screening and diagnostic tool for a number of mental health issues, including depression. When the researchers looked back at where respondents live, they found how far north (less sunlight in winter) or how far south (more equal amounts of sun in all seasons) seemed to have no affect on the frequency of depression.
A separate study on the residents of Tromso, Norway back in 2012 yielded some similar results. Tromso is in northern Norway, near the Arctic Circle. When the sun sets on November 28th every year, it does not rise again until mid-January. You can't get much darker than no sunshine at all for weeks on end. The results showed "no significant differences in the reporting of current mental distress depending on season. Significantly more reported current sleeping problems in winter than in the other seasons, and less sleeping problems were found in spring." But, the 2012 study did conclude that "while some people in the sub-arctic clearly are mentally negatively affected by the darkness of winter, the negative impact of winter on mental distress for the adult population is not conclusive."
So, don't chuck your full-spectrum light box in the trash just yet. Before we dismiss SAD entirely and those who swear they feel run down and depressed in the winter, it'd be worth it to consider two important factors. First, the Auburn study was done looking at major depression. It's possible those just mildly depressed or feeling down didn't register as "depressed" according to the parameters of the research. And second-- and maybe even more importantly-- not every place in the northern tier of U.S. states is equal when it comes to winter weather. Many northern locales, like Minneapolis, get a lot of sunny but cold weather in the winter. Since the Auburn researchers used a cross-section of the United States, their sample size of places that experience both very short days as well as very cloudy weather patterns (our classic NW winter weather) might actually be not well-represented in their survey size.