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Is the dark really making me sad? | Ars Technica

Seasonality is reported by approximately 10 to 20 percent of people with depression and 15 to 22 percent of those with bipolar disorder. “People often don’t realise that there is a continuum between the winter blues—which is a milder form of feeling down, [sleepier and less energetic]—and when this is combined with a major depression,” says Anna Wirz-Justice, an emeritus professor of psychiatric neurobiology at the Centre for Chronobiology in Basel, Switzerland. Even healthy people who have no seasonal problems seem to experience this low-amplitude change over the year, with worse mood and energy during autumn and winter and an improvement in spring and summer, she says.
- arstechnica.com