As someone who grew up in Tromsø, Norway (69 degrees northern latitude), I've always found the idea that long winters and depression go together a strange one (That's not to say there aren't a lot of people in Tromsø that struggle with sleep[1], or that there are no winter depressions).
As a counterpoint to this article's title (but not content, really), there was an interesting piece a while back about seasons and psyche:
TL;DR: Mindset matters. If you don't like winter, then a long dark winter isn't much fun: "The survey results indicated that wintertime mindset may indeed play a role in mental health and well-being in Norway. The Wintertime Mindset Scale had strong positive correlations with every measure of well-being we examined, including the Satisfaction with Life Scale (a widely used survey that measures general life satisfaction), and the Personal Growth Composite (a scale that measures openness to new challenges). The people who had a positive wintertime mindset, in other words, tended to be the same people who were highly satisfied with their lives and who pursued personal growth."
[1] On a somewhat related note, I highly recommend the Norwegian original film "Insomnia" (the basis for the American remake with Al Pacino): http://www.imdb.com/title/tt0119375/
As a counterpoint to this article's title (but not content, really), there was an interesting piece a while back about seasons and psyche:
http://www.theatlantic.com/health/archive/2015/07/the-norweg...
TL;DR: Mindset matters. If you don't like winter, then a long dark winter isn't much fun: "The survey results indicated that wintertime mindset may indeed play a role in mental health and well-being in Norway. The Wintertime Mindset Scale had strong positive correlations with every measure of well-being we examined, including the Satisfaction with Life Scale (a widely used survey that measures general life satisfaction), and the Personal Growth Composite (a scale that measures openness to new challenges). The people who had a positive wintertime mindset, in other words, tended to be the same people who were highly satisfied with their lives and who pursued personal growth."
[1] On a somewhat related note, I highly recommend the Norwegian original film "Insomnia" (the basis for the American remake with Al Pacino): http://www.imdb.com/title/tt0119375/