(Pat Wellenbach | AP photo) This Tuesday, Dec. 18, 2007, photo shows a Christmas wreath decorated with lights at the end of a dock at sunset on Linekin Bay in East Boothbay, Maine. Wintertime can trigger true but transient depression in some people, a condition sometimes called Seasonal Affective Disorder. It's linked with lack of sunlight in winter and some scientists think affected people overproduce the sleep-regulating hormone melatonin. Research suggests it affects about 6 percent of the U.S. population and rates are higher in Scandinavia. But contrary to popular belief, suicides peak in springtime, not winter. No one has figured out why.