GLASGOW, UNITED KINGDOM - OCTOBER 11: A mural painted on a wall is seen through rain drops on October 11, 2005 Glasgow, Scotland. Seasonal affective disorder (SAD), or winter depression, is a mood disorder related to the change in the seasons and the resulting reduction of exposure to daylight. The end of British Summer time, when clocks go back one hour at the end of October, will see most people making their daily commute in darkness both ways. With winter nights stretching to 19 hours in the UK, and Scotland's often inclement weather, it is estimated that the "Winter Blues" can affect up to 20% of the population. (Photo by Christopher Furlong/Getty Images)
