According to google trends this is a peak period for seasonal affective disorder: http://www.google.com/trends?q=seasonal+affective+disorder http://www.google.c

According to google trends this is a peak period for seasonal affective disorder: http://www.google.com/trends?q=seasonal+affective+disorder http://www.google.com/trends?q=seasonal+affective+disorder. Anecdotally, running a few miles a couple times a week improves my mood as well.